A368074 a(n) is the least number k such that the k-th n-gonal number can be written as the difference of two positive n-gonal numbers in exactly n ways.
5, 12, 82, 105, 297, 182
Offset: 3
Examples
a(3) = 5: T(5) = T(6) - T(3) = T(8) - T(6) = T(15) - T(14), where T(k) is the k-th triangular number.
Links
- Eric Weisstein's World of Mathematics, Polygonal Number
Comments