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 A361254 Number of n-regular graphs on 2*n labeled nodes. 1
 1, 1, 3, 70, 19355, 66462606, 2977635137862, 1803595358964773088, 15138592322753242235338875, 1793196665025885172290508971592750, 3040059281615704147007085764679679740691838, 74597015246986083384362428357508730776063716190667288, 26737694395324301026230134763403079891362936970900741153038680278 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS These graphs share the same degree sequence as the complete bipartite graphs K(n,n). LINKS Table of n, a(n) for n=0..12. Atabey Kaygun, Counting Graphs with a Prescribed Degree Sequence Atabey Kaygun, Enumerating Labeled Graphs that Realize a Fixed Degree Sequence, arXiv:2101.02299 [math.CO], 2021. FORMULA a(n) = A059441(2*n, n). PROG (Common Lisp) ; See Links in A339847 for the graph-count function. (defun A361254 (n) (graph-count (loop repeat (* 2 n) collect n))) (PARI) \\ See Links in A295193 for GraphsByDegreeSeq. a(n)={if(n==0, 1, vecsum(GraphsByDegreeSeq(2*n, n, (p, r)->valuation(p, x) >= n-r)[, 2])) } \\ Andrew Howroyd, Mar 06 2023 CROSSREFS Cf. A001223, A059441, A339987, A360437. Sequence in context: A210920 A140048 A135951 * A093245 A108231 A130894 Adjacent sequences: A361251 A361252 A361253 * A361255 A361256 A361257 KEYWORD nonn AUTHOR Atabey Kaygun, Mar 06 2023 EXTENSIONS a(11)-a(12) from Andrew Howroyd, Mar 06 2023 STATUS approved

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Last modified December 2 14:16 EST 2023. Contains 367524 sequences. (Running on oeis4.)