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 A225068 #6 Sep 21 2013 07:30:13 %S A225068 8,1408,2165800,37333296,19384601600,69370076160,69370076160, %T A225068 56288711711232000,7917914554368000000,199449790781142859776 %N A225068 Least octagonal (8-gonal) number that is the product of n octagonal numbers greater than 1. %H A225068 Lars Blomberg, <a href="/A225068/a225068.txt">Table of n, a(n) with solutions for n=1..10</a> %e A225068 Let oct(n) = n*(3n-2). Then %e A225068 a(1) = 8 = oct(2). %e A225068 a(2) = 1408 = oct(22) = oct(2) * oct(8). %e A225068 a(3) = 2165800 = oct(850) = oct(4) * oct(5) * oct(17). %e A225068 a(4) = 37333296 = oct(3528) = oct(3)^2 * oct(8) * oct(13). %e A225068 a(5) = 19384601600 = oct(80384) = oct(2)^2 * oct(5) * oct(14) * oct(53). %e A225068 a(6) = 69370076160 = oct(152064) = oct(3)^3 * oct(4) * oct(7) * oct(22). %Y A225068 Cf. A000567 (octagonal numbers). %Y A225068 Cf. A212616, A212617, A225066-A225070 (3-, 5- to 10-gonal cases). %K A225068 nonn,more %O A225068 1,1 %A A225068 _T. D. Noe_, May 01 2013 %E A225068 Corrected a(4) and added a(7)-a(10) by _Lars Blomberg_, Sep 21 2013