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 A088860 #12 Apr 23 2017 23:56:58 %S A088860 4,12,60,420,4620,60060,1021020,19399380,446185740,12939386460, %T A088860 401120980260,14841476269620,608500527054420,26165522663340060, %U A088860 1229779565176982820,65178316954380089460,3845520700308425278140 %N A088860 Twice the primorials (first definition), 2*A002110(n). %C A088860 Also, least number m divisible by 4 such that omega(m)=n, where omega=A001221. %C A088860 Refers to the least number which is the leg of exactly 2^(n-1) primitive Pythagorean triangles. %C A088860 For n >= 1, a(n) = A097250(n). - _G. C. Greubel_, Apr 23 2017 %H A088860 G. C. Greubel, <a href="/A088860/b088860.txt">Table of n, a(n) for n = 1..345</a> %F A088860 a(n) = 2*#p(n) = 2*A002110(n). %t A088860 2*FoldList[Times, 1, Prime[Range[50]]] (* _G. C. Greubel_, Apr 23 2017 *) %Y A088860 Cf. A002110, A001221, A097250. %K A088860 nonn %O A088860 1,1 %A A088860 _Lekraj Beedassy_, Nov 25 2003 %E A088860 Corrected by _G. C. Greubel_, Apr 23 2017. %E A088860 Edited by _N. J. A. Sloane_, Apr 23 2017