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 A246231 Number of compositions of n into exactly four different parts with distinct multiplicities. 2
 12600, 78120, 189000, 549000, 1389960, 2858640, 6471699, 15289662, 29639082, 64025820, 134997382, 267550925, 545274648, 1161661901, 2223888268, 4552401195, 9185643748, 17829746962, 35102264675, 71613947350, 135793314152, 270167493481, 534784841445 (list; graph; refs; listen; history; text; internal format)
 OFFSET 20,1 LINKS Alois P. Heinz and Vaclav Kotesovec, Table of n, a(n) for n = 20..220 (first 120 terms from Alois P. Heinz) MATHEMATICA b[n_, i_, s_List] := b[n, i, s] = If[n == 0, Total[s]!, If[i<1, 0, Expand[ Sum[ If[j>0 && MemberQ[s, j], 0, If[j == 0, 1, x]*b[n-i*j, i-1, If[j == 0, s, s ~Union~ {j}]]/j!], {j, 0, n/i}]]]]; a[n_] := Coefficient[b[n, n, {}], x, 4]; Table[a[n], {n, 20, 50}] (* Jean-François Alcover, Feb 11 2015, after Alois P. Heinz *) CROSSREFS Column k=4 of A242896. Sequence in context: A237086 A190109 A272516 * A248709 A352586 A261860 Adjacent sequences: A246228 A246229 A246230 * A246232 A246233 A246234 KEYWORD nonn AUTHOR Alois P. Heinz, Aug 19 2014 STATUS approved

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Last modified May 29 00:29 EDT 2024. Contains 372921 sequences. (Running on oeis4.)