cp's OEIS Frontend

A108655 Primes that are sums of the squares of two semiprimes.

%I A108655 #10 Jul 13 2013 12:03:20
%S A108655 97,181,241,277,421,457,541,641,661,709,757,821,1109,1117,1237,1301,
%T A108655 1381,1597,1621,1669,1709,1901,2069,2341,2381,2417,2437,2557,2617,
%U A108655 2677,2741,2797,3041,3061,3221,3557,3637,3701,3733,3989,4241,4261,4421,4517
%N A108655 Primes that are sums of the squares of two semiprimes.
%C A108655 Subsequence of A002144.
%C A108655 a(n) = A074985(i) + A074985(j) for appropriate i and j.
%H A108655 Reinhard Zumkeller, <a href="/A108655/b108655.txt">Table of n, a(n) for n = 1..10000</a>
%e A108655 A000040(733) = 5557 = 81 + 5476 = (3*3)^2 + (2*37)^2 =
%e A108655 A001358(3)^2 + A001358(25)^2 = A074985(3) + A074985(25),
%e A108655 therefore 5557 is a term.
%o A108655 (Haskell)
%o A108655 a108655 n = a108655_list !! (n-1)
%o A108655 a108655_list = filter f a000040_list where
%o A108655    f p = any (> 0) $ map (a064911 . a037213 . (p -)) $
%o A108655                          takeWhile (< p) a074985_list
%o A108655 -- _Reinhard Zumkeller_, Aug 09 2012
%Y A108655 Cf. A000404, A001358, A000290.
%K A108655 nonn
%O A108655 1,1
%A A108655 _Reinhard Zumkeller_, Jul 07 2005