A374194 a(n) is the smallest number which can be represented as the sum of two nonzero hexagonal pyramidal numbers in exactly n ways, or -1 if no such number exists.

2, 5972, 5170425

Offset: 1

Author

Ilya Gutkovskiy, Jun 30 2024

Keywords

• nonn
• hard
• more
• bref

Comments

There are no further positive terms <= 10^15. - Michael S. Branicky, Jun 30 2024

Examples

			a(2) = 5972 = 1222 + 4750 = 1925 + 4047.
		

Links

• Eric Weisstein's World of Mathematics, Hexagonal Pyramidal Number

Crossrefs

Cf. A002412, A011541, A334013, A374141, A374168, A374193.