OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..45
Wikipedia, Partition of a set
EXAMPLE
a(9) = 21146 = 21147 - 1 = A000110(9) - 1 counts all set partitions of [9] except: 1345678|2|9.
MAPLE
b:= proc(n, l) option remember; `if`(n=0, 1, add(b(n-1,
[seq(max(l[i], j), i=2..nops(l)), j]), j=1..l[1]+1))
end:
a:= n-> b(n, [0$6]):
seq(a(n), n=0..20);
MATHEMATICA
b[n_, l_] := b[n, l] = If[n == 0, 1, Sum[b[n - 1, Append[Table[Max[l[[i]], j], {i, 2, Length[l]}], j]], {j, 1, l[[1]] + 1}]];
a[n_] := b[n, Table[0, 6]];
Table[a[n], {n, 0, 20}] (* Jean-François Alcover, May 27 2018, from Maple *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, May 29 2017
STATUS
approved