OFFSET
0,2
COMMENTS
Note that the denominator has 5 tetrahedral numbers: 1, 4, 10, 20, 35.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..645
Index entries for linear recurrences with constant coefficients, signature (70,-1579,13510,-40000,28000).
FORMULA
a(n) = (2736*35^(n+4) - 23715*20^(n+4) + 80104*10^(n+4) - 121125*4^(n+4) + 62000)/1081404000.
MATHEMATICA
CoefficientList[Series[1/((1 - x) (1 - 4 x) (1 - 10 x) (1 - 20 x) (1 - 35 x)), {x, 0, 50}], x] (* G. C. Greubel, Oct 02 2017 *)
PROG
(PARI) Vec(1/((1-x)*(1-4*x)*(1-10*x)*(1-20*x)*(1-35*x)) + O(x^50)) \\ Michel Marcus, May 23 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Yahia Kahloune, Jul 04 2013
EXTENSIONS
Typo in a(7) fixed by Colin Barker, May 23 2014
STATUS
approved