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!)
 A062735 Triangular array T(n,k) giving number of weakly connected digraphs with n labeled nodes and k arcs (n >= 1, 0 <= k <= n(n-1)). 2
 1, 0, 2, 1, 0, 0, 12, 20, 15, 6, 1, 0, 0, 0, 128, 432, 768, 920, 792, 495, 220, 66, 12, 1, 0, 0, 0, 0, 2000, 11104, 33880, 73480, 123485, 166860, 184426, 167900, 125965, 77520, 38760, 15504, 4845, 1140, 190, 20, 1, 0, 0, 0, 0, 0, 41472, 337920, 1536000, 5062080 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS R. J. Mathar, Statistics on Small Graphs, arXiv:1709.09000 (2017) Table 76. FORMULA E.g.f.: 1+log( Sum_{n >= 0, k >= 0} binomial(n*(n-1), k)*x^n/n!*y^k ). EXAMPLE 1; 0, 2, 1; 0, 0, 12, 20,   15,    6,      1; 0, 0, 0, 128,  432,  768,    920,    792,    495,    220,     66,    12, 1; 0, 0, 0,   0, 2000, 11104, 33880,  73480, 123485, 166860, 184426, 167900, ...; 0, 0, 0,   0,    0, 41472, 337920,1536000,5062080,.. ; 0, 0, 0,   0,    0,     0, 1075648,... MATHEMATICA nn=7; s=Sum[(1+y)^(n^2-n) x^n/n!, {n, 0, nn}]; Range[0, nn]!CoefficientList[Series[Log[ s]+1, {x, 0, nn}], {x, y}]//Grid  (* returns triangle indexed from n = 0, Geoffrey Critzer, Oct 07 2012 *) CROSSREFS Cf. (row sums) A003027, (unlabeled case) A054733, diagonal (A097629). Sequence in context: A057274 A088632 A057272 * A054547 A202717 A291195 Adjacent sequences:  A062732 A062733 A062734 * A062736 A062737 A062738 KEYWORD easy,nonn,tabf AUTHOR Vladeta Jovovic, Jul 12 2001 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 September 23 07:59 EDT 2021. Contains 347609 sequences. (Running on oeis4.)