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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.
1
36, 560, 4900, 56448, 4750, 58372180608, 1130220, 6252757280000
OFFSET
2,1
COMMENTS
a(11) = 4200, a(13) = 5521090680, a(14) = 748980.
EXAMPLE
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.
Sequence in context: A329913 A200708 A186309 * A159656 A081447 A218311
KEYWORD
nonn,more
AUTHOR
STATUS
approved