A177400 a(n) = binomial(n*2^n, n).
1, 2, 28, 2024, 635376, 820384032, 4281625192384, 89850821311025280, 7571365534761592422144, 2561263066959640762657702400, 3477982739629565890806006777904128
Offset: 0
Keywords
Crossrefs
Cf. A136463. - Paul D. Hanna, Jul 03 2010
Programs
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Mathematica
Table[Binomial[n 2^n,n],{n,0,20}] (* Harvey P. Dale, Jan 15 2022 *)
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PARI
{a(n)=binomial(n*2^n,n)}
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PARI
{a(n)=polcoeff(sum(k=0, n, n^k*log(1+2^k*x +x*O(x^n))^k/k!), n)} \\ Paul D. Hanna, Jul 03 2010
Formula
a(n) = [x^n] (1 + x)^(n*2^n).
a(n) = [x^n] Sum_{k=0..n} n^k * log(1 + 2^k*x)^k/k!. - Paul D. Hanna, Jul 03 2010