OFFSET
1,2
EXAMPLE
First 7 rows:
1
2...0
3...0...1
4...0...2...0
5...0...4...0...1
6...0...6...2...2...0
7...0...9...4...5...0...1
T(5,3) counts these subsets: {1,2,3}, {1,3,5}, {2,3,4}, {3,4,5}.
MATHEMATICA
t[n_, k_] := Length[Flatten[Map[Apply[Intersection, #] &,
Select[Map[{#, {Mean[#]}} &, Subsets[Range[n], {k}]], IntegerQ[Last[Last[#]]] &]]]]
Flatten[Table[t[n, k], {n, 1, 12}, {k, 1, n}]]
TableForm[Table[t[n, k], {n, 1, 12}, {k, 1, n}]]
(* Peter J. C. Moses, May 01 2012 *)
CROSSREFS
KEYWORD
AUTHOR
Clark Kimberling, May 06 2012
STATUS
approved