OFFSET
1,7
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..1929
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,399,0,0,0,0,-399,0,0,0,0,1).
FORMULA
a(5*k-2) = 3*a(5*k-3) - a(5*k-4) - 1,
a(5*k-1) = 3*a(5*k-2) - a(5*k-3) - 1,
a(5*k) = 3*a(5*k-1) - a(5*k-2) - 1,
a(5*k+1) = 3*a(5*k) - a(5*k-1) - 1,
a(5*k+2) = 8*a(5*k+1) - a(5*k) - 1.
From Colin Barker, Nov 03 2020: (Start)
G.f.: x*(1 + x + x^2 + x^3 + x^4 - 398*x^5 - 393*x^6 - 383*x^7 - 358*x^8 - 293*x^9 + 276*x^10 + 106*x^11 + 41*x^12 + 16*x^13 + 6*x^14) / ((1 - x)*(1 + x + x^2 + x^3 + x^4)*(1 - 398*x^5 + x^10)).
a(n) = 399*a(n-5) - 399*a(n-10) + a(n-15) for n>15.
(End)
MATHEMATICA
a[n_]:= If[n<7, 1, (Sum[a[n-j] , {j, 5}] + a[n - 1] a[n - 5])/a[n - 6]]; Table[a[n], {n, 30}] (* Indranil Ghosh, Mar 18 2017 *)
PROG
(PARI) a(n) = if(n<7, 1, (sum(j=1, 5, a(n - j)) + a(n - 1)*a(n - 5))/a(n - 6));
for(n=1, 30, print1(a(n), ", ")) \\ Indranil Ghosh, Mar 18 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 18 2017
STATUS
approved