A360777 a(n) is the index of the least n-gonal number that is the sum of two or more consecutive nonzero n-gonal numbers in more than one way, or -1 if no such number exists.

9, 160, 143, 2679, 19933, 115248, 45, 1995

Offset: 2

Author

Ilya Gutkovskiy, Feb 20 2023

Keywords

• nonn
• more

Comments

a(10)>2000000, a(11)=24375, a(12)=133307113, a(13)=6715891, a(16)=189308, a(20)=9009. - Sean A. Irvine, Mar 24 2023

Links

• Eric Weisstein's World of Mathematics, Polygonal Number

Crossrefs

Cf. A057145, A360762.