A364373 G.f. satisfies A(x) = (1 + x) * (1 - x*A(x)^4).
1, 0, -1, 4, -12, 26, -14, -236, 1604, -6577, 17827, -14064, -186496, 1437856, -6416576, 18733256, -17358808, -201270728, 1652571996, -7692333934, 23375782030, -23913813710, -250917362258, 2147925544190, -10270145045142, 32053993413694, -35259817590134
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, (-1)^k*binomial(4*k+1, k)*binomial(4*k+1, n-k)/(4*k+1));
Formula
a(n) = Sum_{k=0..n} (-1)^k * binomial(4*k+1,k) * binomial(4*k+1,n-k) / (4*k+1).