This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A225069 #11 Sep 21 2013 07:29:59 %S A225069 9,265926,9909504,28123200,34171875,9833523682950,189619679700, %T A225069 1489258878162739200,32051313254079000000000,231538926078057635957250, %U A225069 5980078350588060426240000 %N A225069 Least nonagonal (9-gonal) number that is the product of n nonagonal numbers greater than 1. %H A225069 Lars Blomberg, <a href="/A225069/a225069.txt">Table of n, a(n) with solutions for n=1..11</a> %e A225069 Let non(n) = n*(7n-5)/2. Then %e A225069 a(1) = 9 = non(2). %e A225069 a(2) = 265926 = non(276) = non(4) * non(41). %e A225069 a(3) = 9909504 = non(1683) = non(3) * non(4) * non(51). %e A225069 a(4) = 28123200 = non(2835) = non(3)^2 * non(5) * non(14). %e A225069 a(5) = 34171875 = non(3125) = non(2)^2 * non(5)^3. %e A225069 a(6) = 9833523682950 = non(1676180) = non(2)^3 * non(6) * non(55) * non(58). %Y A225069 Cf. A001106 (9-gonal or nonagonal numbers). %Y A225069 Cf. A212616, A212617, A225066-A225070 (3-, 5- to 10-gonal cases). %K A225069 nonn,more %O A225069 1,1 %A A225069 _T. D. Noe_, May 01 2013 %E A225069 Corrected a(4)-a(6) and added a(7)-a(11) by _Lars Blomberg_, Sep 21 2013