A225069 Least nonagonal (9-gonal) number that is the product of n nonagonal numbers greater than 1.

9, 265926, 9909504, 28123200, 34171875, 9833523682950, 189619679700, 1489258878162739200, 32051313254079000000000, 231538926078057635957250, 5980078350588060426240000

Offset: 1

Author

T. D. Noe, May 01 2013

Keywords

• nonn
• more

Examples

			Let non(n) = n*(7n-5)/2. Then
a(1) = 9 = non(2).
a(2) = 265926 = non(276) = non(4) * non(41).
a(3) = 9909504 = non(1683) = non(3) * non(4) * non(51).
a(4) = 28123200 = non(2835) = non(3)^2 * non(5) * non(14).
a(5) = 34171875 = non(3125) = non(2)^2 * non(5)^3.
a(6) = 9833523682950 = non(1676180) = non(2)^3 * non(6) * non(55) * non(58).
		

Links

• Lars Blomberg, Table of n, a(n) with solutions for n=1..11

Crossrefs

Cf. A001106 (9-gonal or nonagonal numbers).

Cf. A212616, A212617, A225066-A225070 (3-, 5- to 10-gonal cases).

Extensions

Corrected a(4)-a(6) and added a(7)-a(11) by Lars Blomberg, Sep 21 2013