OFFSET
0,1
COMMENTS
Conjecture: If p is prime, p divides a(p).
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,1,1).
FORMULA
G.f.: (10 - x^9)/(1 - x^9 - x^10).
a(0) = 10 and a(n) = n*Sum_{k=1..floor(n/9)} binomial(k,n-9*k)/k for n > 0.
MATHEMATICA
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 1, 1}, {10, 0, 0, 0, 0, 0, 0, 0, 0, 9}, 80] (* Harvey P. Dale, Jan 18 2021 *)
PROG
(PARI) N=99; x='x+O('x^N); Vec((10-x^9)/(1-x^9-x^10))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Mar 08 2019
STATUS
approved