A374806 a(n) is the smallest number which can be represented as the sum of 3 distinct nonzero triangular numbers in exactly n ways, or -1 if no such number exists.

10, 19, 37, 52, 82, 109, 136, 241, 226, 217, 247, 364, 427, 457, 541, 532, 577, 637, 961, 721, 787, 1066, 1102, 1381, 1267, 1564, 1192, 1396, 1816, 1501, 1612, 1927, 1942, 2242, 1792, 2842, 2587, 2557, 2422, 2866, 2887, 3181, 3271, 3412, 4126

Offset

1,1

Links

Table of n, a(n) for n=1..45.

Eric Weisstein's World of Mathematics, Triangular Number

Example

a(3) = 37 = 1 + 15 + 21 = 3 + 6 + 28 = 6 + 10 + 21.

Crossrefs

Cf. A000217, A025415, A342326, A374807.

Sequence in context: A370916 A085728 A195955 * A127194 A083705 A385924

Adjacent sequences: A374803 A374804 A374805 * A374807 A374808 A374809

Keyword

nonn

Author

Ilya Gutkovskiy, Jul 20 2024

Status

approved