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 A123340 #6 Feb 01 2023 07:07:49
%S A123340 0,0,0,1,0,2,1,1,0,2,2,4,1,3,3,1,0,8,1,4,8,8,6,2,7,27,6,13,1,10,1,6,4,
%T A123340 8,18,9,19,2,15,29,3,3,17,10,3,11,6,2,5,20,34,4,12,10,26,1,4,2,9,29,
%U A123340 29,10,34,13,4,8,2,1,8,10,26,50,19,12,10,8,13,27,17,9,33,4,2,17,1,7,3,5,61,26
%N A123340 Least m such that 2^n+3^m is prime.
%e A123340 a(0)=0 because 2^0+3^0=1+1=2 is prime,
%e A123340 a(3)=1 because 2^3+3^1=8+3=11 is prime,
%e A123340 a(17)=8 because 2^17+3^8=131072+6561=137633 is prime,
%e A123340 a(25)=27 because 33554432+7625597484987=7625631039419 is prime, etc.
%t A123340 a[n_] := Module[{m, t = 2^n}, For[m = 0, True, m++, If[PrimeQ[t + 3^m], Return[m]]]];
%t A123340 Table[a[n], {n, 0, 100}] (* _Jean-François Alcover_, Feb 01 2023 *)
%K A123340 nonn
%O A123340 0,6
%A A123340 _Zak Seidov_, Oct 11 2006