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%I #17 Aug 03 2014 14:01:33
%S 127,197,281,311,347,431,613,659,673,739,877,991,1049,1229,1277,1289,
%T 1367,1481,1579,1613,1667,1721,1787,1877,1907,2027,2081,2087,2141,
%U 2203,2213,2237,2239,2269,2287,2309,2377,2383,2473,2657,2689,2707,2749,2767,2801
%N 2.5-gap primes: Prime p is a term if there is no prime between 2.5*p and 2.5*q, where q is the next prime after p.
%t Select[Prime[Range[500]], PrimePi[5*NextPrime[#]/2] == PrimePi[5*#/2] &] (* _T. D. Noe_, Sep 20 2011 *)
%Y Cf. A195270, A195271, A195325, A194658, A164294.
%K nonn
%O 1,1
%A _Vladimir Shevelev_, Sep 17 2011