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 A227027 #6 Jul 05 2013 04:49:15 %S A227027 6,120,210,990,7140,185136,242556,2162160,8239770,258474216,279909630, %T A227027 9508687656,323015470680,10973017315470,372759573255306, %U A227027 12662852473364940,430164224521152660,14612920781245825506,496409142337836914550 %N A227027 Triangular numbers representable as x!/y! with y < x-1. %C A227027 Triangular numbers in A045619, except A045619(1)=0. The sequence is infinite because A029549 is a subsequence. According to Melissen's comment in A097571, y > x-7. %C A227027 The sequence of x's producing a(n): A227026. %C A227027 a(2) and a(3) have two representations: %C A227027 a(2) = 120 = 5*4*3*2 = 6*5*4. %C A227027 a(3) = 210 = 7*6*5 = 15*14. %e A227027 990 is in the sequence since 990 = 11!/8! = 11*10*9 is a ratio of factorials and 990 = (44)(44 + 1)/2 is a triangular number. %Y A227027 Cf. A000217, A001219, A029549, A045619, A097571, A227026. %K A227027 nonn %O A227027 1,1 %A A227027 _Alex Ratushnyak_, Jun 27 2013