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 A385705 #13 Jul 08 2025 10:42:57
%S A385705 37,61,109,139,157,181,193,233,269,283,347,349,353,367,373,379,487,
%T A385705 521,541,563,571,593,613,617,619,641,643,709,727,739,797,811,823,829,
%U A385705 853,857,877,907,983,991,1033,1051,1097,1103,1117,1193,1217,1229,1231,1237
%N A385705 Primes p such that there exists prime q < p such that sigma(p+1)=sigma(q+1).
%H A385705 S. I. Dimitrov, <a href="https://arxiv.org/abs/2408.07387">Generalizations of amicable numbers</a>, arXiv:2408.07387 [math.NT], 2024.
%e A385705 (41, 61) is such a pair because sigma(41+1)=sigma(61+1) = 96.
%t A385705 s={};Do[Do[If[DivisorSigma[1,Prime[m]+1]==DivisorSigma[1,Prime[n]+1],AppendTo[s,Prime[n]];Break[]],{m,n-1}],{n,203}];s (* _James C. McMahon_, Jul 08 2025 *)
%o A385705 (PARI) isok(p) = my(s=sigma(p+1)); forprime(q=1, p-1, if (sigma(q+1)==s, return(q))); \\ _Michel Marcus_, Jul 07 2025
%Y A385705 Cf. A000203, A000040, A008333, A385586 (a subsequence).
%K A385705 nonn,easy
%O A385705 1,1
%A A385705 _S. I. Dimitrov_, Jul 07 2025