A088860 - OEIS

%I #12 Apr 23 2017 23:56:58

%S 4,12,60,420,4620,60060,1021020,19399380,446185740,12939386460,

%T 401120980260,14841476269620,608500527054420,26165522663340060,

%U 1229779565176982820,65178316954380089460,3845520700308425278140

%N Twice the primorials (first definition), 2*A002110(n).

%C Also, least number m divisible by 4 such that omega(m)=n, where omega=A001221.

%C Refers to the least number which is the leg of exactly 2^(n-1) primitive Pythagorean triangles.

%C For n >= 1, a(n) = A097250(n). - _G. C. Greubel_, Apr 23 2017

%H G. C. Greubel, <a href="/A088860/b088860.txt">Table of n, a(n) for n = 1..345</a>

%F a(n) = 2*#p(n) = 2*A002110(n).

%t 2*FoldList[Times, 1, Prime[Range[50]]] (* _G. C. Greubel_, Apr 23 2017 *)

%Y Cf. A002110, A001221, A097250.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Nov 25 2003

%E Corrected by _G. C. Greubel_, Apr 23 2017.

%E Edited by _N. J. A. Sloane_, Apr 23 2017