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 A307369 a(n) = -Sum_{0<=i
 0, 0, 3, -51, 1059, -23090, 522721, -12147685, 287854454, -6924261148, 168559758222, -4143307764311, 102667574424349, -2561308686267644, 64269232404321663, -1620744761933019015, 41050609554433557263, -1043736712034774976330, 26628094150076388266301 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS MATHEMATICA Table[-Sum[Sum[Sum[(-1)^(i+j+k) * (i + j + k)!/(i!*j!*k!), {i, 0, j-1}], {j, 0, k-1}], {k, 0, n}], {n, 0, 20}] (* Amiram Eldar, May 20 2021 *) PROG (PARI) {a(n) = -sum(i=0, n, sum(j=i+1, n, sum(k=j+1, n, (-1)^(i+j+k)*(i+j+k)!/(i!*j!*k!))))} CROSSREFS Cf. A306409, A306432, A307358. Sequence in context: A145242 A182512 A075869 * A126685 A355797 A246693 Adjacent sequences:  A307366 A307367 A307368 * A307370 A307371 A307372 KEYWORD sign AUTHOR Seiichi Manyama, Apr 05 2019 STATUS approved

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Last modified August 19 03:31 EDT 2022. Contains 356216 sequences. (Running on oeis4.)