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 A144658 a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} (i+j+k)!/(i!*j!*k!). 2
 0, 6, 222, 5052, 109512, 2432448, 55611294, 1301187912, 30992726652, 748573575780, 18283412752602, 450657126652626, 11192820097106112, 279787295335659972, 7032532241701837758, 177611430241032329568 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..100 MATHEMATICA Table[Sum[Sum[Sum[(i+j+k)!/i!/j!/k!, {i, 1, n}], {j, 1, n}], {k, 1, n}], {n, 1, 30}] PROG (PARI) {a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, (i+j+k)!/(i!*j!*k!))))} \\ Seiichi Manyama, May 19 2019 (PARI) {a(n) = sum(i=3, 3*n, i!*polcoef(sum(j=1, n, x^j/j!)^3, i))} \\ Seiichi Manyama, May 19 2019 CROSSREFS Cf. A144511. Sequence in context: A292692 A015477 A331477 * A203637 A144045 A061610 Adjacent sequences:  A144655 A144656 A144657 * A144659 A144660 A144661 KEYWORD nonn AUTHOR N. J. A. Sloane, Jan 30 2009 STATUS approved

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Last modified March 28 17:51 EDT 2020. Contains 333103 sequences. (Running on oeis4.)