A320853 Number of 7-element subsets of [n] whose sum is a triangular number.

1, 1, 5, 14, 36, 84, 174, 337, 613, 1058, 1749, 2787, 4304, 6463, 9476, 13598, 19140, 26486, 36079, 48461, 64263, 84209, 109160, 140100, 178144, 224578, 280871, 348655, 429780, 526341, 640642, 775262, 933082, 1117259, 1331289, 1579031, 1864697, 2192905

Offset: 7

Author

Alois P. Heinz, Oct 22 2018

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 7..1000

Crossrefs

Column k=7 of A284249.

Cf. A000217.