A373706 Expansion of 1/(1 - x * (1 + x^4)^2).
1, 1, 1, 1, 1, 3, 5, 7, 9, 12, 19, 30, 45, 64, 91, 134, 201, 300, 440, 641, 939, 1386, 2050, 3021, 4437, 6516, 9588, 14128, 20811, 30624, 45042, 66268, 97545, 143604, 211368, 311040, 457704, 673605, 991437, 1459215, 2147563, 3160516, 4651330, 6845572, 10075042
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,2,0,0,0,1).
Programs
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PARI
a(n) = sum(k=0, 2*n\9, binomial(2*n-8*k, k));
Formula
a(n) = a(n-1) + 2*a(n-5) + a(n-9) for n > 8.
a(n) = Sum_{k=0..floor(2*n/9)} binomial(2*n-8*k,k).
a(n) = A005711(2*n-1) for n > 0.