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 A202942 G.f.: [ Sum_{n>=0} (n+1)*(n+2)/2 * 2^(n^2) * x^n ]^(1/3). 4
 1, 2, 28, 1592, 320416, 233502272, 640425828736, 6752822665196288, 276674110514780283136, 44326172948662599528407552, 27888135883706078415361423227904, 69119744225611603596101581358820128768, 676455661208111898411893322163207326229331968 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(2*n) == 1 (mod 3); a(2*n+1) == 2 (mod 3). EXAMPLE G.f.: A(x) = 1 + 2*x + 28*x^2 + 1592*x^3 + 320416*x^4 + 233502272*x^5 +... where A(x)^3 = 1 + 3*2*x + 6*2^4*x^2 + 10*2^9*x^3 + 15*2^16*x^4 + 21*2^25*x^5 +... PROG (PARI) {a(n)=polcoeff(sum(m=0, n, (m+1)*(m+2)/2*2^(m^2)*x^m+x*O(x^n))^(1/3), n)} CROSSREFS Sequence in context: A063794 A331839 A238817 * A326366 A177400 A230700 Adjacent sequences:  A202939 A202940 A202941 * A202943 A202944 A202945 KEYWORD nonn AUTHOR Paul D. Hanna, Dec 26 2011 STATUS approved

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Last modified June 17 23:41 EDT 2021. Contains 345088 sequences. (Running on oeis4.)