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 A342738 #17 Mar 24 2021 15:53:09 %S A342738 5,7,19,41,197,2549,4159,8467,9433,26701,27551,46817,57037,91097, %T A342738 130859,153281,157049,197683,351727,423103,466181,517991,526291, %U A342738 567181,575231,652903,663167,772339,1055231,1062013,1088239,1171199,1232461,1551871,1603297,1662833,2782469,2920531,2957917,3226159 %N A342738 Primes p such that A001414(p+1) = A001414(p-1) + 1. %H A342738 Robert Israel, <a href="/A342738/b342738.txt">Table of n, a(n) for n = 1..1000</a> %e A342738 a(3) = 19 is a term because it is prime and A001414(20) = 9 = 1 + A001414(18). %p A342738 spf:= proc(n) local t; add(t[1]*t[2],t=ifactors(n)[2]) end proc: %p A342738 select(p -> spf(p+1)=spf(p-1)+1, [seq(ithprime(i),i=1..10^5)]); %Y A342738 Cf. A001414, A086711, A342823. %K A342738 nonn %O A342738 1,1 %A A342738 _J. M. Bergot_ and _Robert Israel_, Mar 22 2021