A379284 G.f. A(x) satisfies A(x) = 1/((1 - x*A(x)^2) * (1 - x*A(x)^4)).
1, 2, 15, 158, 1943, 26099, 371128, 5491868, 83692617, 1304579981, 20703125143, 333366138381, 5433036837372, 89448269251685, 1485469625972490, 24854484773368344, 418581393456669989, 7090045259711970090, 120706208890692261466, 2064356606197948427512, 35449776962011108029539
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, binomial(2*n+3*k+1, k)*binomial(3*n+k, n-k)/(2*n+3*k+1));
Formula
a(n) = Sum_{k=0..n} binomial(2*n+3*k+1,k) * binomial(3*n+k,n-k)/(2*n+3*k+1).