A374168 a(n) is the smallest number which can be represented as the sum of two nonzero square pyramidal numbers in exactly n ways, or -1 if no such number exists.

2, 60, 9692375

Offset

1,1

Comments

There are no further positive terms <= 10^15. - Michael S. Branicky, Jul 01 2024

Links

Table of n, a(n) for n=1..3.

Eric Weisstein's World of Mathematics, Square Pyramidal Number.

Example

a(2) = 60 = 5 + 55 = 30 + 30.

Crossrefs

Cf. A000330, A011541, A016032, A334013, A374193, A374194.

Sequence in context: A121493 A078491 A182856 * A101896 A130411 A262079

Adjacent sequences: A374165 A374166 A374167 * A374169 A374170 A374171

Keyword

nonn,hard,bref,more

Author

Ilya Gutkovskiy, Jun 30 2024

Status

approved