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A244101
Number of ballot sequences of length n having 4 largest parts.
2
1, 0, 0, 0, 14, 42, 90, 165, 737, 3003, 15652, 55965, 236924, 851224, 3872838, 16766607, 83026979, 390791373, 1941965432, 9380708953, 47629991554, 241035098010, 1284641489560, 6852122431245, 38078198632749, 211138699725567, 1208307893511470, 6916339675763595
OFFSET
4,5
COMMENTS
Also number of standard Young tableaux with last row of length 4.
LINKS
MATHEMATICA
b[n_, l_List] := b[n, l] = If[n < 1, x^l[[-1]], b[n - 1, Append[l, 1]] + Sum[If[i == 1 || l[[i - 1]] > l[[i]], b[n - 1, ReplacePart[l, i -> l[[i]] + 1]], 0], {i, 1, Length[l]}]]; a[n_] := Coefficient[b[n - 1, {1}], x, 4]; Table[a[n], {n, 4, 30}] (* Jean-François Alcover, Feb 10 2015, after A238123 *)
CROSSREFS
Column k=4 of A238123.
Sequence in context: A356452 A163756 A005587 * A212514 A292051 A242897
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jun 20 2014
STATUS
approved