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Semiprimes == -+1 (mod 8).
1

%I #11 Mar 21 2020 09:53:37

%S 9,15,25,33,39,49,55,57,65,87,95,111,119,121,129,143,145,159,161,169,

%T 177,183,185,201,209,215,217,247,249,265,287,289,295,303,305,319,321,

%U 327,329,335,361,377,391,393,407,415,417,447,471,473,481,489,497,505

%N Semiprimes == -+1 (mod 8).

%H Daniel Starodubtsev, <a href="/A176404/b176404.txt">Table of n, a(n) for n = 1..10000</a>

%p isA001358 := proc(n) numtheory[bigomega](n) = 2 ; end proc: for n from 1 to 600 do if n mod 8 in {1,7} and isA001358(n) then printf("%d,",n) ; end if; end do: # _R. J. Mathar_, Apr 20 2010

%Y Cf. A001358.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Apr 16 2010

%E Corrected (247, 287 inserted) by _R. J. Mathar_, Apr 20 2010