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 A227888 #16 Oct 29 2013 14:49:22 %S A227888 3,1,19,3,19,273,93,113,87,35,31,143,31,15,315,779,207,347,91,327,291, %T A227888 351,195,39,1911,971,1083,435,1345,593,183,1295,291,2553,735,1113,31, %U A227888 131,61,209,379,567,2331,1907,4429,23,453,1517,2281,2187,1441,4847,1975 %N A227888 Smallest odd k such that k*2^n-1, k*2^n-1+2*j, k*2^n-1+4*j or k*2^n-1-2*j, k*2^n-1, k*2^n-1+2*j are consecutive primes in arithmetic progression for some j. %H A227888 Pierre CAMI, <a href="/A227888/b227888.txt">Table of n, a(n) for n = 1..325</a> %e A227888 3*2^1-1-2=3 3*2^1-1=5 3*2^1-1+2=7 so a(1)=3. %e A227888 3*2^4-1=47 3*2^4-1+6=53 3*2^4-1+12=59 so a(4)=3. %Y A227888 Cf. A052187. %K A227888 nonn %O A227888 1,1 %A A227888 _Pierre CAMI_, Oct 26 2013