OFFSET
7,1
COMMENTS
Also the number of ballot sequences of length n where 7 is the position of the last occurrence of the minimal value.
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 7..75
Wikipedia, Young tableau
MATHEMATICA
b[n_, l_List] := b[n, l] = If[n == 0, 1, Sum[If[i == 1 || l[[i - 1]] > l[[i]], b[n - 1, ReplacePart[l, i -> l[[i]] + 1]], 0], {i, 1, Length[l]}] + Function[{p}, p + (x^(1 + Total[l]) - 1)*Coefficient[p, x, 0]][b[n - 1, Append[l, 1]]]]; a[n_] := Coefficient[b[n, {}], x, 7]; Table[Print["a(", n, ") = ", an = a[n]]; an , {n, 7, 40}] (* Jean-François Alcover, Feb 06 2015, after Maple code in A238794 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jul 09 2014
STATUS
approved