A364734 G.f. satisfies A(x) = 1 + x*A(x) / (1 - x*A(x)^5).
1, 1, 2, 9, 48, 276, 1687, 10750, 70597, 474478, 3247844, 22563904, 158693152, 1127661358, 8083795761, 58390722901, 424562043703, 3104994695198, 22825260066996, 168564068029385, 1249985066423749, 9303815610715531, 69483859839881494, 520527161650519576
Offset: 0
Keywords
Programs
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PARI
a(n) = if(n==0, 1, sum(k=0, n-1, binomial(n, k)*binomial(n+4*k, n-1-k))/n);
Formula
a(n) = (1/n) * Sum_{k=0..n-1} binomial(n,k) * binomial(n+4*k,n-1-k) for n > 0.