A320852 Number of 6-element subsets of [n] whose sum is a triangular number.

1, 1, 4, 11, 26, 55, 106, 190, 321, 518, 804, 1207, 1763, 2511, 3502, 4794, 6447, 8541, 11163, 14407, 18382, 23215, 29040, 36005, 44284, 54059, 65529, 78918, 94466, 112434, 133104, 156783, 183803, 214518, 249307, 288580, 332774, 382358, 437829, 499717, 568579

Offset

6,3

Links

Alois P. Heinz, Table of n, a(n) for n = 6..1000

Crossrefs

Column k=6 of A284249.

Cf. A000217.

Sequence in context: A109414 A027966 A141534 * A192961 A290989 A027660

Adjacent sequences: A320849 A320850 A320851 * A320853 A320854 A320855

Keyword

nonn

Author

Alois P. Heinz, Oct 22 2018

Status

approved