A350397 a(n) is the smallest number which can be represented as the sum of n distinct nonzero n-gonal pyramidal numbers in exactly n ways, or -1 if no such number exists.
305, 1980, 1900, 3321, 5256, 8310, 12516, 17108, 24832, 34249, 42381, 61697, 78766, 106956, 132994, 170325, 203415, 266595, 322943, 393828, 475520, 569416, 695799, 823447, 958300, 1149125, 1313545, 1565055, 1802736, 2088119, 2376250, 2748270, 3135195, 3548876
Offset: 3
Keywords
Examples
For n = 3: 305 = 1 + 84 + 220 = 20 + 120 + 165 = 56 + 84 + 165.
Links
- Martin Ehrenstein, Table of n, a(n) for n = 3..52
- Eric Weisstein's World of Mathematics, Pyramidal Number
Extensions
a(10)-a(22) from Michael S. Branicky, Dec 29 2021
a(23)-a(36) from Martin Ehrenstein, Jan 14 2022