Displaying 1-9 of 9 results found.
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a(n) = ((7*n+9)(!^7))/9(!^7), related to A034829 (((7*n+2)(!^7))/2 sept-, or 7-factorials).
+20
3
1, 16, 368, 11040, 408480, 17973120, 916629120, 53164488960, 3455691782400, 248809808332800, 19655974858291200, 1690413837813043200, 157208486916613017600, 15720848691661301760000
COMMENTS
Row m=9 of the array A(8; m,n) := ((7*n+m)(!^7))/m(!^7), m >= 0, n >= 0.
FORMULA
a(n) = ((7*n+9)(!^7))/9(!^7)= A034829(n+2)/9.
E.g.f.: 1/(1-7*x)^(16/7).
MATHEMATICA
CoefficientList[Series[1/(1-7x)^(16/7), {x, 0, 20}], x]Range[0, 20]! (* Harvey P. Dale, Sep 11 2011 *)
PROG
(PARI) x='x+O('x^30); Vec(serlaplace(1/(1-7*x)^(16/7))) \\ G. C. Greubel, Aug 16 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1/(1-7*x)^(16/7))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Aug 16 2018
One seventh of sept-factorial numbers.
+10
11
1, 14, 294, 8232, 288120, 12101040, 592950960, 33205253760, 2091930986880, 146435169081600, 11275508019283200, 947142673619788800, 86189983299400780800, 8446618363341276518400, 886894928150834034432000, 99332231952893411856384000, 11820535602394316010909696000
FORMULA
7*a(n) = (7*n)(!^7) = Product_{j=1..n} 7*j = 7^n*n!.
E.g.f.: x/(1-7*x).
Sum_{n>=1} 1/a(n) = 7*(exp(1/7)-1).
Sum_{n>=1} (-1)^(n+1)/a(n) = 7*(1-exp(-1/7)). (End)
MATHEMATICA
Table[7^(n-1)*n!, {n, 1, 30}] (* or *) Drop[With[{nn = 50}, CoefficientList[ Series[x/(1-7*x), {x, 0, nn}], x]*Range[0, nn]!], 1] (* G. C. Greubel, Feb 22 2018 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(serlaplace(x/(1-7*x))) \\ G. C. Greubel, Feb 22 2018
(Magma) [7^(n-1)*Factorial(n): n in [1..30]]; // G. C. Greubel, Feb 22 2018
a(n) = n-th sept-factorial number divided by 3.
+10
9
1, 10, 170, 4080, 126480, 4806240, 216280800, 11246601600, 663549494400, 43794266630400, 3196981464019200, 255758517121536000, 22250990989573632000, 2091593153019921408000, 211250908455012062208000, 22815098113141302718464000, 2623736283011249812623360000
FORMULA
3*a(n) = (7*n-4)(!^7) = Product_{j=1..n} (7*j-4).
E.g.f.: (-1 + (1-7*x)^(-3/7))/3.
Sum_{n>=1} 1/a(n) = 3*(e/7^4)^(1/7)*(Gamma(3/7) - Gamma(3/7, 1/7)). (End)
MATHEMATICA
Drop[With[{nn = 40}, CoefficientList[Series[(-1 + (1 - 7*x)^(-3/7))/3, {x, 0, nn}], x]*Range[0, nn]!], 1] (* G. C. Greubel, Feb 23 2018 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(serlaplace((-1 + (1-7*x)^(-3/7))/3)) \\ G. C. Greubel, Feb 23 2018
a(n) = n-th sept-factorial number divided by 6.
+10
9
1, 13, 260, 7020, 238680, 9785880, 469722240, 25834723200, 1601752838400, 110520945849600, 8399591884569600, 697166126419276800, 62744951377734912000, 6086260283640286464000, 632971069498589792256000, 70259788714343466940416000, 8290655068292529098969088000
FORMULA
a(n) = (7*n-1)(!^7)/6;
a(n) = (1/6)*Product_{j=1..n} (7*j-1);
E.g.f.: (-1 + (1-7*x)^(-6/7))/6.
Sum_{n>=1} 1/a(n) = 6*(e/7)^(1/7)*(Gamma(6/7) - Gamma(6/7, 1/7)). - Amiram Eldar, Dec 20 2022
MATHEMATICA
FoldList[Times, 1, Rest[7*Range[20]-1]] (* Harvey P. Dale, Dec 15 2014 *)
PROG
(PARI) my(x='x+('x^30)); Vec(serlaplace((-1 + (1-7*x)^(-6/7))/6)) \\ G. C. Greubel, Feb 22 2018
(Magma) [(&*[(7*k-1): k in [1..n]])/6: n in [1..30]]; // G. C. Greubel, Feb 24 2018
a(n) = n-th sept-factorial number divided by 5.
+10
8
1, 12, 228, 5928, 195624, 7824960, 367773120, 19859748480, 1211444657280, 82378236695040, 6178367752128000, 506626155674496000, 45089727855030144000, 4328613874082893824000, 445847229030538063872000, 49043195193359187025920000, 5738053837623024882032640000
FORMULA
5*a(n) = (7*n-2)(!^7) = Product_{j=1..n} (7*j-2).
E.g.f.: (-1 + (1-7*x)^(-5/7))/5.
Sum_{n>=1} 1/a(n) = 5*(e/7^2)^(1/7)*(Gamma(5/7) - Gamma(5/7, 1/7)). (End)
MATHEMATICA
Rest[FoldList[Times, 1, 7*Range[20]-2]/5] (* Harvey P. Dale, May 30 2013 *)
Drop[With[{nn = 50}, CoefficientList[Series[(-1 + (1 - 7*x)^(-5/7))/5, {x, 0, nn}], x]*Range[0, nn]!], 1] (* G. C. Greubel, Feb 22 2018 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(serlaplace((-1 + (1-7*x)^(-5/7))/5)) \\ G. C. Greubel, Feb 22 2018
a(n) = n-th sept-factorial number divided by 4.
+10
7
1, 11, 198, 4950, 158400, 6177600, 284169600, 15060988800, 903659328000, 60545174976000, 4480342948224000, 362907778806144000, 31935884534940672000, 3033909030819363840000, 309458721143575111680000, 33731000604649687173120000, 3912796070139363712081920000
FORMULA
4*a(n) = (7*n-3)(!^7) = Product_{j=1..n} (7*j-3).
E.g.f.: (-1 + (1-7*x)^(-4/7))/4.
Sum_{n>=1} 1/a(n) = 4*(e/7^3)^(1/7)*(Gamma(4/7) - Gamma(4/7, 1/7)). (End)
MATHEMATICA
Drop[With[{nn = 40}, CoefficientList[Series[(-1 + (1 - 7*x)^(-4/7))/4, {x, 0, nn}], x]*Range[0, nn]!], 1] (* G. C. Greubel, Feb 22 2018 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(serlaplace((-1 + (1-7*x)^(-4/7))/4)) \\ G. C. Greubel, Feb 22 2018
(Magma) [(&*[(7*k-3): k in [1..n]])/4: n in [1..30]]; // G. C. Greubel, Feb 24 2018
Expansion of 1/(1-49*x)^(1/7); related to sept-factorial numbers A045754.
+10
6
1, 7, 196, 6860, 264110, 10722866, 450360372, 19365495996, 847240449825, 37560993275575, 1682732498745760, 76028913806967520, 3459315578217022160, 158330213003009860400, 7283189798138453578400, 336483368673996555322080
FORMULA
a(n) = 7^n* A045754(n)/n!, n >= 1, A045754(n) = (7*n-6)(!^7) := product(7*j-6, j=1..n); G.f.: (1-49*x)^(-1/7).
D-finite with recurrence: n*a(n) +7*(-7*n+6)*a(n-1)=0. - R. J. Mathar, Jan 28 2020
MATHEMATICA
CoefficientList[Series[1/(1 - 49*x)^(1/7), {x, 0, 50}], x] (* G. C. Greubel, Feb 22 2018 *)
PROG
(PARI) x='x+O('x^30); Vec(1/(1 - 49*x)^(1/7)) \\ G. C. Greubel, Feb 22 2018
(Magma) Q:=Rationals(); R<x>:=PowerSeriesRing(Q, 40); Coefficients(R!(1/(1 - 49*x)^(1/7))) // G. C. Greubel, Feb 22 2018
a(n) = ((7*n+10)(!^7))/10(1^7), related to A034830 (((7*n+3)(!^7))/3 sept-, or 7-factorials).
+10
5
1, 17, 408, 12648, 480624, 21628080, 1124660160, 66354949440, 4379426663040, 319698146401920, 25575851712153600, 2225099098957363200, 209159315301992140800, 21125090845501206220800
COMMENTS
Row m=10 of the array A(8; m,n) := ((7*n+m)(!^7))/m(!^7), m >= 0, n >= 0.
FORMULA
a(n) = ((7*n+10)(!^7))/10(!^7) = A034830(n+2)/10.
E.g.f.: 1/(1-7*x)^(17/7).
MATHEMATICA
With[{nn = 30}, CoefficientList[Series[1/(1 - 7*x)^(17/7), {x, 0, nn}], x]*Range[0, nn]!] (* G. C. Greubel, Aug 16 2018 *)
PROG
(PARI) x='x+O('x^30); Vec(serlaplace(1/(1-7*x)^(17/7))) \\ G. C. Greubel, Aug 16 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1/(1-7*x)^(17/7))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Aug 16 2018
a(n) = ((7*n+8)(!^7))/8, related to A045754 ((7*n+1)(!^7) sept-, or 7-factorials).
+10
4
1, 15, 330, 9570, 344520, 14814360, 740718000, 42220926000, 2702139264000, 191851887744000, 14964447244032000, 1271978015742720000, 117021977448330240000, 11585175767384693760000
COMMENTS
Row m=8 of the array A(8; m,n) := ((7*n+m)(!^7))/m(!^7), m >= 0, n >= 0.
FORMULA
a(n) = ((7*n+8)(!^7))/8(!^7) = A045754(n+2)/8.
E.g.f.: 1/(1-7*x)^(15/7).
MATHEMATICA
With[{nn = 30}, CoefficientList[Series[1/(1 - 7*x)^(15/7), {x, 0, nn}], x]*Range[0, nn]!] (* G. C. Greubel, Aug 16 2018 *)
PROG
(PARI) x='x+O('x^30); Vec(serlaplace(1/(1-7*x)^(15/7))) \\ G. C. Greubel, Aug 16 2018
(Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1/(1-7*x)^(15/7))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, Aug 16 2018
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