This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A195271 #11 Aug 03 2014 14:01:33 %S A195271 2,5,17,29,41,79,101,137,149,163,191,197,227,269,281,313,349,353,461, %T A195271 463,521,541,569,593,599,613,617,641,757,769,809,821,827,857,881,887, %U A195271 941,1009,1049,1061,1087,1093,1097,1117,1151,1223,1229,1277,1279,1289 %N A195271 1.5-gap primes: Prime p is a term iff there is no prime between 1.5*p and 1.5*q, where q is the next prime after p. %C A195271 For a real r>1, a prime p is called an r-gap prime, if there is no prime between r*p and r*q, where q is the next prime after p. In particular, 2-gap primes form A080192 and 3-gap primes form A195270. %t A195271 Select[Prime[Range[400]], PrimePi[3*NextPrime[#]/2] == PrimePi[3*#/2] &] (* _T. D. Noe_, Sep 14 2011 *) %Y A195271 Cf. A080192, A195270, A193507, A194186, A164368, A194598, A194658, A194659, A194674, A164288, A164294. %K A195271 nonn %O A195271 1,1 %A A195271 _Vladimir Shevelev_, Sep 14 2011