OFFSET
0,5
LINKS
Robert Israel, Table of n, a(n) for n = 0..3321
Mathematics StackExchange, Let S = 1,2,3,4,...,2070 find the number of subsets of S whose sum of elements in S is divisible by 9
Robert Israel, Proof of conjectured g.f.
FORMULA
Empirical G.f.: -(4*x^12-2*x^9-x^7+2*x^6+2*x^5+2*x^4-3*x^3-x^2-x+1) / ((2*x-1)*(2*x^3-1)*(2*x^9-1)). [Colin Barker, Dec 22 2012]
Empirical G.f. verified: see link. - Robert Israel, Apr 30 2019
MAPLE
G:= Array(0..100, 0..8):
G[0, 0]:= 1; for j from 1 to 8 do G[0, j]:= 0 od:
for n from 1 to 100 do
for j from 0 to 8 do
k:= j - n mod 9;
G[n, j]:= G[n-1, j] + G[n-1, k];
od od:
seq(G[n, 0], n=0..100); # Robert Israel, Apr 30 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Feb 11 2002
STATUS
approved