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%I #5 Dec 05 2013 19:56:33
%S 3,5,23,17,157,191,383,257,2557,9209,6143,20477,73721,147449,360439,
%T 65537,655357,786431,11010029,5242877,31457267,71303153,276824033,
%U 150994937,301989881,469762043,671088637,4026531827,2684354557
%N Smallest prime obtained as a sum of n terms of a geometric progression + the common ratio, or 0 if no such terms exists. Smallest prime of the form (a +ar +ar^2 + ar^3 +... ) + r.
%C The ratio is required to be > 1.
%C For a(5), (1 + r + r^2 + r^3 + r^4) + r is composite. hence the first term of the geometric progression is >1. For a(5) a = 5 and r = 2. This is true For all odd n.
%e a(3) = (3+6+12) + 2 = 23.
%e a(4) = (1+2+4+8 ) + 2 = 17.
%e a(6) = (3+6+12+24+48+96) + 2= 191.
%Y Cf. A088120.
%K easy,nonn
%O 1,1
%A _Amarnath Murthy_, Sep 25 2003
%E More terms from _David Wasserman_, Jul 25 2005
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