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

7,3

Links

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

Crossrefs

Column k=7 of A284249.

Cf. A000217.

Sequence in context: A234097 A211562 A261055 * A193557 A187198 A097507

Adjacent sequences: A320850 A320851 A320852 * A320854 A320855 A320856

Keyword

nonn

Author

Alois P. Heinz, Oct 22 2018

Status

approved