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 A171799 O.g.f.: Sum_{n>=0} 2^(n^2)*x^n/(1 - 2^n*x)^n. 2
 1, 2, 20, 648, 78608, 37949472, 74258600000, 589859028828288, 18957096840069579008, 2455889836782322072945152, 1278835681226410156250000000000, 2671465293024628033252951422140418048 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n) = 2^n*(2^n + 1)^(n-1) for n>0 with a(0)=1. EXAMPLE G.f.: A(x) = 1 + 2*x + 20*x^2 + 648*x^3 + 78608*x^4 +... A(x) = 1 + 2*x/(1-2*x) + 2^4*x^2/(1-2^2*x)^2 + 2^9*x^3/(1-2^3*x)^3 +... PROG (PARI) {a(n)=polcoeff(sum(m=0, n, 2^(m^2)*x^m/(1-2^m*x+x*O(x^n))^m), n)} (PARI) {a(n)=if(n==0, 1, 2^n*(2^n+1)^(n-1))} CROSSREFS Cf. A171801, A171800, A136516. Sequence in context: A012495 A168480 A198761 * A158268 A168407 A163594 Adjacent sequences:  A171796 A171797 A171798 * A171800 A171801 A171802 KEYWORD nonn AUTHOR Paul D. Hanna, Jan 20 2010 STATUS approved

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