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 A207556 G.f.: Sum_{n>=0} (1+x)^n * Product_{k=1..n} ((1+x)^k - 1). 4
 1, 1, 3, 11, 55, 339, 2499, 21433, 209717, 2305719, 28141925, 377579731, 5523750291, 87508680045, 1492510215135, 27266981038343, 531245913925837, 10995334516297279, 240925208376757203, 5571653169126500083, 135617881389268715939, 3465772763274106884733 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Compare g.f. to: Sum_{n>=0} Product_{k=1..n} ((1+x)^k - 1), which is the g.f. of A179525. LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..170 FORMULA a(n) ~ 2 * 12^(n+1) * n^(n+1/2) / (exp(n+Pi^2/24) * Pi^(2*n+3/2)). - Vaclav Kotesovec, May 07 2014 EXAMPLE G.f.: A(x) = 1 + x + 3*x^2 + 11*x^3 + 55*x^4 + 339*x^5 + 2499*x^6 +... such that, by definition, A(x) = 1 + (1+x)*((1+x)-1) + (1+x)^2*((1+x)-1)*((1+x)^2-1) + (1+x)^3*((1+x)-1)*((1+x)^2-1)*((1+x)^3-1) + (1+x)^4*((1+x)-1)*((1+x)^2-1)*((1+x)^3-1)*((1+x)^4-1) +... PROG (PARI) {a(n)=polcoeff(sum(m=0, n, (1+x)^m*prod(k=1, m, (1+x)^k-1) +x*O(x^n)), n)} for(n=0, 25, print1(a(n), ", ")) CROSSREFS Cf. A179525, A207557. Sequence in context: A125696 A001776 A261001 * A180875 A136104 A174627 Adjacent sequences:  A207553 A207554 A207555 * A207557 A207558 A207559 KEYWORD nonn AUTHOR Paul D. Hanna, Feb 18 2012 STATUS approved

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Last modified December 14 05:36 EST 2019. Contains 329978 sequences. (Running on oeis4.)