OFFSET
1,1
COMMENTS
Also, least number m divisible by 4 such that omega(m)=n, where omega=A001221.
Refers to the least number which is the leg of exactly 2^(n-1) primitive Pythagorean triangles.
For n >= 1, a(n) = A097250(n). - G. C. Greubel, Apr 23 2017
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..345
FORMULA
a(n) = 2*#p(n) = 2*A002110(n).
MATHEMATICA
2*FoldList[Times, 1, Prime[Range[50]]] (* G. C. Greubel, Apr 23 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Lekraj Beedassy, Nov 25 2003
EXTENSIONS
Corrected by G. C. Greubel, Apr 23 2017.
Edited by N. J. A. Sloane, Apr 23 2017
STATUS
approved