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 A355073 G.f.: Sum_{n>=0} a(n)*x^n/(n!*3^(n*(n-1)/2)) = exp( Sum_{n>=1} x^n/(n!*3^(n*(n-1)/2)) ). 2
 1, 1, 4, 55, 2539, 383860, 187659181, 293630900689, 1459799672901004, 22924423319469919651, 1131844225175191511724871, 175015470856131731421651730600, 84480805958219938739735661779357401, 126948830401157131161305967764668449231937 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Table of n, a(n) for n=0..13. PROG (PARI) a(n) = n!*3^(n*(n-1)/2)*polcoef(exp(sum(k=1, n, x^k/(k!*3^(k*(k-1)/2)))+x*O(x^n)), n); (PARI) T(n, k) = if(k==1, 1, sum(j=1, n-1, 3^(j*(n-j))*binomial(n-1, j)*T(j, k-1))); a(n) = if(n==0, 1, sum(k=1, n, T(n, k))); CROSSREFS Cf. A000110, A240936, A355074. Cf. A355070, A355081. Sequence in context: A099122 A001500 A246968 * A054751 A189873 A358542 Adjacent sequences: A355070 A355071 A355072 * A355074 A355075 A355076 KEYWORD nonn AUTHOR Seiichi Manyama, Jun 18 2022 STATUS approved

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Last modified June 8 10:57 EDT 2023. Contains 363164 sequences. (Running on oeis4.)