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 A136652 L.g.f.: A(x) = log( Sum_{n>=0} 2^[n(n-1)/2]*x^n ). 2
 1, 3, 19, 223, 4771, 190023, 14441659, 2130394591, 616038609331, 351153716973303, 395928966997611499, 885010943452285951183, 3928049212346654960720611, 34658088824057172975437120103 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE L.g.f.: A(x) = x + 3*x^2/2 + 19*x^3/3 + 223*x^4/4 + 4771*x^5/5 +... A(x) = log(1 + x + 2x^2 + 8x^3 + 64x^4 + 1024x^5 +...+ 2^(n(n-1)/2)*x^n +...). PROG (PARI) a(n)=n*polcoeff(log(sum(k=0, n, 2^(k*(k-1)/2)*x^k +x*O(x^n))), n) CROSSREFS Cf. A136653, A136654. Sequence in context: A001035 A217906 A166380 * A136504 A003111 A160888 Adjacent sequences:  A136649 A136650 A136651 * A136653 A136654 A136655 KEYWORD nonn AUTHOR Paul D. Hanna, Jan 15 2008 STATUS approved

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