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A101346
a(n) = binomial(2^n, n-1).
5
1, 4, 28, 560, 35960, 7624512, 5423611200, 13161885792000, 110859231254749120, 3293259778311548232704, 349928324708588104171703296, 134575849279352109587517966790656, 189165427620415586720308268784807487488, 979739920960712963224129514007339757999308800
OFFSET
1,2
LINKS
FORMULA
G.f.: A(x) = x*Sum_{n>=0} 2^n*log(1+2^n*x)^n/n!. - Paul D. Hanna, Jun 21 2009
a(n) ~ 2^(n*(n-1)) / (n-1)!. - Vaclav Kotesovec, Jul 02 2016
MAPLE
seq(binomial(2^n, n-1), n=1..20);
MATHEMATICA
Table[Binomial[2^n, n-1], {n, 1, 15}] (* Vaclav Kotesovec, Jul 02 2016 *)
PROG
(PARI) a(n)=binomial(2^n, n-1) \\ Paul D. Hanna, Jun 21 2009
(PARI) a(n)=polcoeff(x*sum(k=0, n, 2^k*log(1+2^k*x+x*O(x^n))^k/k!), n) \\ Paul D. Hanna, Jun 21 2009
CROSSREFS
Cf. A014070. - Paul D. Hanna, Jun 21 2009
Sequence in context: A111817 A134048 A091969 * A120604 A203279 A081792
KEYWORD
nonn
AUTHOR
Jorge Coveiro, Dec 25 2004
EXTENSIONS
Terms a(13) and beyond from Andrew Howroyd, Feb 12 2020
STATUS
approved