A374141 a(n) is the smallest number which can be represented as the sum of two distinct nonzero hexagonal numbers in exactly n ways, or -1 if no such number exists.

7, 384, 4995, 51106, 204805, 483031, 2443431, 4674256, 10476781, 17272531, 25600656, 60765331, 90406956, 206602126, 332808531, 481676406, 303826656, 435211156, 789949306, 1406495106, 2260173906, 2704798281, 3220562556, 4435869181, 5165053156, 5309576106, 9818788281

Offset

1,1

Links

Michael S. Branicky, Table of n, a(n) for n = 1..39

Michael S. Branicky, Python program for A374141, A374142, and A374143

Eric Weisstein's World of Mathematics, Hexagonal Number

Example

a(2) = 384 = 6 + 378 = 153 + 231.

Prog

(Python) # see linked program

Crossrefs

Cf. A000384, A093195, A332989, A342326, A374142, A374143.

Sequence in context: A367868 A372814 A299036 * A112905 A293459 A058275

Adjacent sequences: A374138 A374139 A374140 * A374142 A374143 A374144

Keyword

nonn

Author

Ilya Gutkovskiy, Jun 28 2024

Extensions

a(9)-a(27) from Michael S. Branicky, Jun 29 2024

Status

approved