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 A367460 #23 Mar 02 2024 13:51:19
%S A367460 1,10,52,400,2480,7202,28222
%N A367460 Numbers k such that 3^sigma(k) - k is a prime.
%C A367460 a(8) > 67569.
%e A367460 10 is in the sequence because 3^sigma(10) - 10 = 3^18 - 10 = 387420479 is prime.
%t A367460 a[n_] := Select[Range@ n, PrimeQ[3^DivisorSigma[1, #] - #] &]; a[20000]
%t A367460 DeleteCases[ParallelTable[If[PrimeQ[3^DivisorSigma[1,k]-k],k,n],{k,1,10^4}],n]
%o A367460 (Magma) [n: n in[1..10000] | IsPrime((3^SumOfDivisors(n)) - n)]
%Y A367460 Cf. A000043, A000203, A000668, A023194, A023195, A253850, A253851, A368651.
%K A367460 nonn,more
%O A367460 1,2
%A A367460 _J.W.L. (Jan) Eerland_, Jan 26 2024
%E A367460 a(7) from _Michael S. Branicky_, Jan 27 2024