%I A133431
%S A133431 1,2,3,4,5,7,10,11,12,14,15,18,24,25,26,28,29,31,33,35,38,39,42,43,46,
               49,50,53,56,
%T A133431 59,63,64,67,68,75,81,82,87,89,91,92,94,96,106,109,120,124,126,129,130,
               137,141,
%U A133431 143,148,154,157,158,159,165,166,171,172,173,176,180,185,186,187,192,194,
               196,197
%N A133431 Old-fashioned version of A002504 (the initial 1 should be omitted since 
               1 is no longer regarded as a prime, although it was in 1912).
%D A133431 A. J. C. Cunningham, On quasi-Mersennian numbers, Mess. Math., 41 (1912), 
               119-146.
%Y A133431 Sequence in context: A047502 A117092 A002504 this_sequence A123091 A160512 
               A144430
%Y A133431 Adjacent sequences: A133428 A133429 A133430 this_sequence A133432 A133433 
               A133434
%K A133431 nonn
%O A133431 1,2
%A A133431 N. J. A. Sloane (njas(AT)research.att.com), Nov 28 2007