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Search: a139196 -id:a139196
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Numbers k such that (k!-4)/4 is prime.
+10
20
4, 5, 6, 7, 8, 10, 15, 18, 23, 157, 165, 183, 184, 362, 611, 908, 2940, 6875, 9446, 16041
OFFSET
1,1
COMMENTS
Numbers k such that (k!-m)/m is prime:
for m=1 see A002982
for m=2 prime or pseudoprime see A082671
for m=3 see A139056
for m=4 see A139199
for m=5 see A139200
for m=6 see A139201
for m=7 see A139202
for m=8 see A139203
for m=9 see A139204
for m=10 see A139205
a(17) > 2000 - Ray G. Opao, Sep 30 2008
a(21) > 25000 - Robert Price, Sep 25 2016
MATHEMATICA
a = {}; Do[If[PrimeQ[(n! - 4)/4], Print[a]; AppendTo[a, n]], {n, 1, 184}]; a (*Artur Jasinski*)
PROG
(PARI) is(n)=n>3 && isprime(n!/4-1) \\ Charles R Greathouse IV, Apr 29 2015
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
a(15)-a(16) from Ray G. Opao, Sep 30 2008
a(17) from Serge Batalov, Feb 18 2015
a(18)-a(20) from Robert Price, Sep 25 2016
STATUS
approved
Numbers k such that (k!-10)/10 is prime.
+10
20
5, 6, 7, 11, 13, 17, 28, 81, 87, 433, 640, 647, 798, 1026, 1216, 1277, 3825, 6684
OFFSET
1,1
COMMENTS
a(19) > 25000. - Robert Price, Dec 23 2016
MATHEMATICA
a = {}; Do[If[PrimeQ[(n! - 10)/10], Print[a]; AppendTo[a, n]], {n, 1, 300}]; a (*Artur Jasinski*)
Select[Range[700], PrimeQ[(#!-10)/10]&] (* Harvey P. Dale, Feb 15 2015 *)
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
One additional term (a(12)) from Harvey P. Dale, Feb 15 2015
More terms from Serge Batalov, Feb 18 2015
a(18) from Robert Price, Dec 23 2016
STATUS
approved
a(n) = prime(n)!-1.
+10
19
1, 5, 119, 5039, 39916799, 6227020799, 355687428095999, 121645100408831999, 25852016738884976639999, 8841761993739701954543615999999, 8222838654177922817725562879999999, 13763753091226345046315979581580902399999999, 33452526613163807108170062053440751665151999999999, 60415263063373835637355132068513997507264511999999999, 258623241511168180642964355153611979969197632389119999999999, 4274883284060025564298013753389399649690343788366813724671999999999999, 138683118545689835737939019720389406345902876772687432540821294940159999999999999
OFFSET
1,2
COMMENTS
Numbers of the form (prime(n)!-m)/m :
for m=1 see A139189
for m=2 see A139190
for m=3 see A139191
for m=4 see A139192
for m=5 see A139193
for m=6 see A139194
for m=7 see A139195
for m=8 see A139196
for m=9 see A139197
for m=10 see A139198
LINKS
FORMULA
a(n)=A039716(n)-1. - R. J. Mathar, May 25 2008
MATHEMATICA
Table[(Prime[n]! - 1)/1, {n, 1, 20}]
PROG
(PARI) a(n) = prime(n)!-1 \\ Charles R Greathouse IV, Apr 29 2015
(Magma) [(Factorial(NthPrime(n))-1): n in [1..20]]; // Vincenzo Librandi, Jun 02 2017
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
More terms from R. J. Mathar, May 25 2008
STATUS
approved
Natural numbers of the form (prime(n)!-3)/3.
+10
19
1, 39, 1679, 13305599, 2075673599, 118562476031999, 40548366802943999, 8617338912961658879999, 2947253997913233984847871999999, 2740946218059307605908520959999999, 4587917697075448348771993193860300799999999, 11150842204387935702723354017813583888383999999999, 20138421021124611879118377356171332502421503999999999, 86207747170389393547654785051203993323065877463039999999999, 1424961094686675188099337917796466549896781262788937908223999999999999
OFFSET
1,2
FORMULA
a(n)=(A139189(n+1)-2)/3. - R. J. Mathar, May 25 2008
MATHEMATICA
Table[(Prime[n]! - 3)/3, {n, 2, 20}]
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
More terms from R. J. Mathar, May 25 2008
STATUS
approved
a(n) = (prime(n)!-2)/2.
+10
18
0, 2, 59, 2519, 19958399, 3113510399, 177843714047999, 60822550204415999, 12926008369442488319999, 4420880996869850977271807999999, 4111419327088961408862781439999999, 6881876545613172523157989790790451199999999, 16726263306581903554085031026720375832575999999999, 30207631531686917818677566034256998753632255999999999, 129311620755584090321482177576805989984598816194559999999999, 2137441642030012782149006876694699824845171894183406862335999999999999
OFFSET
1,2
LINKS
FORMULA
a(n) = (A139189(n)-1)/2. - R. J. Mathar, May 25 2008
MATHEMATICA
Table[(Prime[n]! - 2)/2, {n, 1, 20}]
PROG
(PARI) a(n) = (prime(n)!-2)/2 \\ Charles R Greathouse IV, Apr 29 2015
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
More terms from R. J. Mathar, May 25 2008
STATUS
approved
a(n) = (prime(n)! - 4)/4.
+10
18
29, 1259, 9979199, 1556755199, 88921857023999, 30411275102207999, 6463004184721244159999, 2210440498434925488635903999999, 2055709663544480704431390719999999, 3440938272806586261578994895395225599999999, 8363131653290951777042515513360187916287999999999, 15103815765843458909338783017128499376816127999999999, 64655810377792045160741088788402994992299408097279999999999, 1068720821015006391074503438347349912422585947091703431167999999999999
OFFSET
3,1
LINKS
FORMULA
a(n) = (A139189(n+2) - 3)/4. - R. J. Mathar, May 25 2008
MATHEMATICA
Table[(Prime[n]! - 4)/4, {n, 3, 20}]
PROG
(Magma) [(Factorial(NthPrime(n))-4)/4: n in [3..20]]; // Vincenzo Librandi, Jun 02 2017
(PARI) a(n) = (prime(n)!-4)/4;
lista(nn) = for (n=3, nn, print1(a(n), ", ")); \\ Michel Marcus, Feb 17 2018
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
More terms from R. J. Mathar, May 25 2008
STATUS
approved
Natural numbers of the form (prime(n)! - 5)/5.
+10
18
23, 1007, 7983359, 1245404159, 71137485619199, 24329020081766399, 5170403347776995327999, 1768352398747940390908723199999, 1644567730835584563545112575999999
OFFSET
1,1
MAPLE
A039716 := proc(n) factorial(ithprime(n)) ; end: A139193 := proc(n) A039716(n)/5-1 ; end: seq(A139193(n), n=3..14) ; # R. J. Mathar, Sep 18 2009
MATHEMATICA
Table[(Prime[n]! - 5)/5, {n, 3, 20}]
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
STATUS
approved
Natural numbers of the form (prime(n)!-6)/6.
+10
18
0, 19, 839, 6652799, 1037836799, 59281238015999, 20274183401471999, 4308669456480829439999, 1473626998956616992423935999999, 1370473109029653802954260479999999
OFFSET
1,2
MATHEMATICA
Table[(Prime[n]! - 6)/6, {n, 2, 20}]
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
STATUS
approved
(prime(n)!-7)/7.
+10
18
719, 5702399, 889574399, 50812489727999, 17377871486975999, 3693145248412139519999, 1263108856248528850649087999999, 1174691236311131831103651839999999, 1966250441603763578045139940225843199999999
OFFSET
4,1
COMMENTS
Not an integer for n < 4.
MATHEMATICA
Table[(Prime[n]! - 7)/7, {n, 4, 20}]
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
Edited with one more term by Franklin T. Adams-Watters, Apr 09 2009
STATUS
approved
Natural numbers of the form (prime(n)!-9)/9.
+10
18
559, 4435199, 691891199, 39520825343999, 13516122267647999, 2872446304320552959999, 982417999304411328282623999999, 913648739353102535302840319999999
OFFSET
1,1
MATHEMATICA
Table[(Prime[n]! - 9)/9, {n, 4, 20}]
(Prime[Range[4, 20]]!-9)/9 (* Harvey P. Dale, Apr 10 2019 *)
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
STATUS
approved

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