A376650 a(n) = Sum_{k=0..floor(n/4)} binomial(floor(k/3),n-4*k).
1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 3, 3, 1, 1, 3, 3, 1, 1, 3, 3, 1, 1, 4, 6, 4, 2, 4, 6, 4, 2, 4, 6, 4, 2, 5, 10, 10, 6, 6, 10, 10, 6, 6, 10, 10, 6, 7, 15, 20, 16, 12, 16, 20, 16, 12, 16, 20, 16, 13, 22, 35, 36
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,0,0,1,1).
Programs
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PARI
a(n) = sum(k=0, n\4, binomial(k\3, n-4*k));
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PARI
my(N=90, x='x+O('x^N)); Vec((1+x^4+x^8)/(1-x^12-x^13))
Formula
G.f.: (1-x^12)/((1-x^4) * (1-x^12-x^13)) = (1+x^4+x^8)/(1-x^12-x^13).
a(n) = a(n-12) + a(n-13).