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 A057676 #16 Jul 13 2025 13:05:03
%S A057676 2,3,3,19,19,13,13,19,37,3,19,31,31,67,127,379,607,31,19,577,181,67,
%T A057676 97,31,349,619,97,919,31,211,577,181,13,397,31,829,19,577,577,103,
%U A057676 1669,199,19,31,439,1021,601,1621,2017,733,3,199,2113,619,1861,1297,241,967
%N A057676 Smallest prime q such that 2^prime(n) - q is prime.
%H A057676 Amiram Eldar, <a href="/A057676/b057676.txt">Table of n, a(n) for n = 1..560</a>
%e A057676 For n = 4, prime(4) = 11, 2^11 = 2048, p2 = 2048-p1 is satisfied at first with prime p1 = 19 resulting in prime p2 = 2029, so a(4) = 19.
%e A057676 For n = 31, prime(31) = 127, p2 = 2^127-p1 is satisfied first with p1 = 577 and p2 = 170141183460469231731687303715884105151, so a(31) = 577.
%t A057676 spq[n_]:=Module[{p=2,t=2^Prime[n]},While[!PrimeQ[t-p],p=NextPrime[p]];p]; Array[spq,60] (* _Harvey P. Dale_, Jul 13 2025 *)
%o A057676 (PARI) a(n) = {my(p = 1 << prime(n), q = 2); while(!isprime(p - q), q = nextprime(q + 1)); q;} \\ _Amiram Eldar_, Feb 18 2025
%Y A057676 Cf. A057662, A056206, A056208.
%K A057676 nonn
%O A057676 1,1
%A A057676 _Labos Elemer_, Oct 19 2000
%E A057676 Offset corrected by _Amiram Eldar_, Feb 18 2025