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Numbers n such that (10's complement factorial of n) + 1 is semiprime.
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%I #8 Dec 15 2017 17:36:55

%S 1,3,6,14,20,21,26,34,37,39,40,47,51,54,61,62,72,74,77,82,83,86,113,

%T 115,118,127,139,179

%N Numbers n such that (10's complement factorial of n) + 1 is semiprime.

%o (PARI) comp(n)=10^#Str(n)-n

%o is(n)=bigomega(prod(k=1,n,comp(k))+1)==2 \\ _Charles R Greathouse IV_, Jul 10 2011

%Y Cf. A110396, A109616.

%K nonn,base

%O 1,2

%A _Jason Earls_, Aug 12 2005

%E More terms from _Sean A. Irvine_, Jul 10 2011