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A376647
a(n) = Sum_{k=0..floor(n/3)} binomial(floor(k/2),n-3*k).
1
1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 2, 1, 1, 2, 1, 1, 3, 3, 2, 3, 3, 2, 4, 6, 5, 5, 6, 5, 6, 10, 11, 10, 11, 11, 11, 16, 21, 21, 21, 22, 22, 27, 37, 42, 42, 43, 44, 49, 64, 79, 84, 85, 87, 93, 113, 143, 163, 169, 172, 180, 206, 256, 306, 332, 341, 352, 386, 462, 562
OFFSET
0,14
FORMULA
G.f.: (1-x^6)/((1-x^3) * (1-x^6-x^7)) = (1+x^3)/(1-x^6-x^7).
a(n) = a(n-6) + a(n-7).
a(n) = A017847(n) + A017847(n-3).
PROG
(PARI) a(n) = sum(k=0, n\3, binomial(k\2, n-3*k));
(PARI) my(N=80, x='x+O('x^N)); Vec((1+x^3)/(1-x^6-x^7))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Oct 01 2024
STATUS
approved