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%I #4 Mar 30 2012 17:22:47
%S 7,13,41,113,97,193,641,769,11777,13313,59393,12289,40961,114689,
%T 163841,2424833,6946817,786433,5767169,7340033,23068673,155189249,
%U 595591169,1224736769,167772161,469762049,2281701377,3489660929,12348030977
%N Least prime of the form 1 + p*2^n, where p is an odd prime.
%C a(n) least prime such that A098006(pi(a(n))) = 2^(n-1). See A134855 for the values of p.
%H T. D. Noe, <a href="/A134854/b134854.txt">Table of n, a(n) for n=1..1000</a>
%t Table[Select[1+2^n*Prime[Range[2,100]], PrimeQ, 1][[1]], {n,41}]
%K nonn
%O 1,1
%A _T. D. Noe_, Nov 13 2007