A320849 Number of 3-element subsets of [n] whose sum is a triangular number.

1, 1, 3, 5, 8, 12, 16, 22, 29, 37, 46, 57, 69, 82, 97, 114, 131, 150, 171, 194, 219, 245, 273, 302, 334, 368, 404, 441, 480, 522, 567, 613, 660, 710, 762, 818, 876, 936, 997, 1061, 1127, 1196, 1268, 1342, 1419, 1498, 1580, 1664, 1751, 1841, 1934, 2029, 2127

Offset

3,3

Links

Alois P. Heinz, Table of n, a(n) for n = 3..10000

Crossrefs

Column k=3 of A284249.

Cf. A000217.

Sequence in context: A183139 A094913 A265060 * A255981 A020678 A310034

Adjacent sequences: A320846 A320847 A320848 * A320850 A320851 A320852

Keyword

nonn

Author

Alois P. Heinz, Oct 22 2018

Status

approved