A374499 Least n-gonal pyramidal number that can be written as a product of two or more smaller n-gonal pyramidal numbers, or 0 if no such number exists.

36, 560, 4900, 56448, 4750, 58372180608, 1130220, 6252757280000

Offset: 2

Author

Pontus von Brömssen, Jul 09 2024

Keywords

• nonn
• more

Comments

a(11) = 4200, a(13) = 5521090680, a(14) = 748980.

Examples

			For 2 <= n <= 9, the n-gonal pyramidal number a(n) can be written as a product of smaller n-gonal pyramidal numbers in the following ways:
  n |             a(n)
  --+-------------------------------------
  2 |            36 = 6*6
  3 |           560 = 4*4*35 = 10*56
  4 |          4900 = 5*5*14*14
  5 |         56448 = 196*288
  6 |          4750 = 50*95
  7 |   58372180608 = 196*456*653108
  8 |       1130220 = 9*70*1794
  9 | 6252757280000 = 10*10*10*80*78159466
		

Crossrefs

Second column of A374498.

Cf. A080851, A374371.