OFFSET
1,1
COMMENTS
Positive numbers of the form 4*n^2 - 1 which are semiprimes can be found in A037074.
Or, all positive products of the form A014076(i)*[A014076(i)+-2], duplicates removed. - R. J. Mathar, Aug 08 2007
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..5000
FORMULA
MATHEMATICA
Select[4*(Range[54])^2-1, Not[PrimeQ[Sqrt[(#+ 1)]-1] && PrimeQ[Sqrt[(#+1)]+1]]&]
Select[4*Range[100]^2-1, PrimeOmega[#]!=2&] (* Harvey P. Dale, Jul 24 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Nov 16 2006
EXTENSIONS
Edited by N. J. A. Sloane, Aug 03 2007
STATUS
approved