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 A236143 #8 Jan 19 2014 11:32:51 %S A236143 7,11,31,67,179,193,197,281,347,349,563,599,757,1123,1453,1543,1933, %T A236143 1987,2083,2531,2971,3037,3259,3547,3583,3701,3919,4027,4483,5023, %U A236143 5581,5591,5647,5981,6449,7207,7297,7603,8291,9049 %N A236143 Odd primes p with prime(p-1) - (p-1) and prime(p-1) - 2*prime((p-1)/2) both prime. %C A236143 By part (i) of the conjecture in A236138, this sequence should have infinitely many terms. %H A236143 Zhi-Wei Sun, <a href="/A236143/b236143.txt">Table of n, a(n) for n = 1..10000</a> %e A236143 a(1) = 7 with prime(6) - 6 = 13 - 6 = 7 and prime(6) - 2*prime(3) = 13 - 2*5 = 3 both prime. %t A236143 PQ[n_]:=n>0&&PrimeQ[n] %t A236143 p[n_]:=PrimeQ[Prime[n-1]-(n-1)]&&PQ[Prime[n-1]-2*Prime[(n-1)/2]] %t A236143 n=0;Do[If[p[Prime[k]],n=n+1;Print[n," ",Prime[k]]],{k,2,10^5}] %o A236143 (PARI) s=[]; forprime(p=3, 10000, if(isprime(prime(p-1)-(p-1)) && isprime(prime(p-1)-2*prime((p-1)/2)), s=concat(s, p))); s \\ _Colin Barker_, Jan 19 2014 %Y A236143 Cf. A000040, A234695, A235925, A236075, A236119, A236138. %K A236143 nonn %O A236143 1,1 %A A236143 _Zhi-Wei Sun_, Jan 19 2014