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 A206848 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k^2) ). 6
 1, 2, 5, 53, 3422, 826606, 1335470713, 9548109569885, 190076214495558260, 18558289189760778318731, 10286810587274357297985552184, 16301371794177939084545371104827679, 91249944361047494534207504939405352235731, 3283593155431496336538359592977826684908598341441 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Logarithmic derivative yields A206849. Equals row sums of triangle A228902. LINKS Seiichi Manyama, Table of n, a(n) for n = 0..57 EXAMPLE G.f.: A(x) = 1 + 2*x + 5*x^2 + 53*x^3 + 3422*x^4 + 826606*x^5 + 1335470713*x^6 +... where the logarithm of the g.f. yields the l.g.f. of A206849: log(A(x)) = 2*x + 6*x^2/2 + 137*x^3/3 + 13278*x^4/4 + 4098627*x^5/5 +... PROG (PARI) {a(n)=polcoeff(exp(sum(m=1, n, sum(k=0, m, binomial(m^2, k^2))*x^m/m)+x*O(x^n)), n)} for(n=0, 25, print1(a(n), ", ")) CROSSREFS Cf. A206849 (log), A206846, A206850, A228902. Cf. variants: A167006, A228809. Sequence in context: A330282 A071880 A071882 * A081482 A134475 A218030 Adjacent sequences: A206845 A206846 A206847 * A206849 A206850 A206851 KEYWORD nonn AUTHOR Paul D. Hanna, Feb 15 2012 STATUS approved

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Last modified April 24 05:26 EDT 2024. Contains 371918 sequences. (Running on oeis4.)