The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A207135 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k*(n-k)) ). 6
 1, 2, 5, 32, 796, 77508, 26058970, 28765221688, 101824384364586, 1145306676113095172, 40618070255705049577152, 4523562146025746408072408406, 1576501611479138389748204925102907, 1714649258669533421310212170714443813118 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The logarithmic derivative yields A207136. Equals the row sums of triangle A228900. Equals the self-convolution of A228852. LINKS EXAMPLE G.f.: A(x) = 1 + 2*x + 5*x^2 + 32*x^3 + 796*x^4 + 77508*x^5 +... where the logarithm of the g.f. equals the l.g.f. of A207136: log(A(x)) = 2*x + 6*x^2/2 + 74*x^3/3 + 2942*x^4/4 + 379502*x^5/5 +... PROG (PARI) {a(n)=polcoeff(exp(sum(m=1, n, x^m/m*sum(k=0, m, binomial(m^2, k*(m-k))))+x*O(x^n)), n)} for(n=0, 20, print1(a(n), ", ")) CROSSREFS Cf. A207136 (log), A167006, A228900, A206830, A206850, A228852. Sequence in context: A005636 A067299 A203227 * A118325 A224231 A019037 Adjacent sequences:  A207132 A207133 A207134 * A207136 A207137 A207138 KEYWORD nonn AUTHOR Paul D. Hanna, Feb 15 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified February 17 12:32 EST 2020. Contains 331996 sequences. (Running on oeis4.)