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 A094382 #8 Mar 30 2012 18:50:44 %S A094382 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,2,2,2,2,2,2, %T A094382 2,2,2,2,2,2,3,3,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,7,7,7,7,7,7,7,7,7,7, %U A094382 7,7,7,7,7,7,7,7,7,7,8,8,8,8,9,9,9,9,9,9,9,9,9,9,9,9,9,9,11,11,11,11 %N A094382 Number of quadruples (p, p+d, p+2*d, p+3*d) of primes with d>0 and p+3*d<=n. %H A094382 <a href="/index/Pri#primes_AP">Index entries for sequences related to primes in arithmetic progressions</a> %e A094382 a(50)=4: 5=prime(3) -> 5+6=11=prime(5) -> 11+6=17=prime(7) -> %e A094382 17+6=23=prime(9), 5=prime(3) -> 5+12=17=prime(7) -> 17+12=29=prime(10) -> %e A094382 29+12=41=prime(13), 7=prime(4) -> 7+12=19=prime(8) -> 19+12=31=prime(11) -> %e A094382 31+12=43=prime(14) and 11=prime(5) -> 11+6=17=prime(7) -> 17+6=23=prime(9) %e A094382 -> 23+6=29=prime(10), %Y A094382 Cf. A093354, A094383. %K A094382 nonn %O A094382 1,29 %A A094382 _Reinhard Zumkeller_, Apr 28 2004