OFFSET
1,2
COMMENTS
The semiprimes of this form are: 4, 85, 365, 445, 533, 629, 965, 1685, 1853, 2605, 2813, 3029, 3973, 4765, 5045, 5629, 5933, 6245, ...
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[0, 300], PrimeOmega[#^2 + 4] == 2 &]
PROG
(Magma) IsSemiprime:=func<i | &+[d[2]: d in Factorization(i)] eq 2>; [n: n in [0..300] | IsSemiprime(s) where s is n^2+4];
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, May 14 2014
STATUS
approved