A368075 a(n) is the least n-gonal number that can be expressed as the difference of two positive n-gonal numbers in exactly n ways.

15, 144, 10045, 21945, 220077, 99008

Offset

3,1

Comments

The corresponding indices of n-gonal numbers are in A368074.

Links

Table of n, a(n) for n=3..8.

Eric Weisstein's World of Mathematics, Polygonal Number

Example

a(3) = 15: 15 = 21 - 6 = 36 - 21 = 120 - 105.

Crossrefs

Cf. A086270, A338105, A368041, A368074.

Sequence in context: A243418 A270511 A026893 * A163799 A206810 A025440

Adjacent sequences: A368072 A368073 A368074 * A368076 A368077 A368078

Keyword

nonn,more

Author

Ilya Gutkovskiy, Dec 10 2023

Status

approved