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 A342823 #10 Mar 24 2021 15:53:32 %S A342823 29,127,449,571,727,1721,4027,11969,16987,18913,26449,37139,43609, %T A342823 48871,48953,63799,64781,114479,180847,220021,400031,400597,476911, %U A342823 607549,679969,705883,706841,770059,776449,807539,912367,932177,964793,1007959,1052237,1095851,1356227,1444567,1573339,1664633 %N A342823 Primes p such that A001414(p+1) = A001414(p-1) - 1. %H A342823 Robert Israel, <a href="/A342823/b342823.txt">Table of n, a(n) for n = 1..1100</a> %e A342823 a(3) = 449 is a term because it is prime and A001414(450) = 18 = A001414(448) - 1. %p A342823 spf:= proc(n) local t; add(t[1]*t[2],t=ifactors(n)[2]) end proc: %p A342823 select(p -> spf(p+1)=spf(p-1)-1, [seq(ithprime(i),i=1..10^5)]); %Y A342823 Cf. A001414, A086711, A342738. %K A342823 nonn %O A342823 1,1 %A A342823 _J. M. Bergot_ and _Robert Israel_, Mar 22 2021