OFFSET
0,9
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..300
Index entries for linear recurrences with constant coefficients, signature (2, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 1).
FORMULA
G.f.: (x^6 (1+x (-1+x (1+(-1+x) x))))/(1+x (-2+x (1+x^11 (-1+(2-x) x)))). - Peter J. C. Moses, Jun 01 2014
a(n)= +2*a(n-1) -a(n-2) +a(n-13) -2*a(n-14) +a(n-15). - R. J. Mathar, Aug 11 2021
MATHEMATICA
Table[Floor[n(n-1)/26], {n, 0, 600}] (* G. C. Greubel, Sep 03 2015 *)
Join[{0}, Floor[#/13]&/@Accumulate[Range[0, 70]]] (* Harvey P. Dale, Apr 26 2020 *)
PROG
(PARI) a(n) = n*(n-1)\26; \\ G. C. Greubel, Sep 03 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved