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 A178328 #22 Jun 26 2023 06:33:34
%S A178328 2,21,121,211,223,631,1211,1663,1811,1831,2127,2813,4211,5497,6211,
%T A178328 8411,12149,12287,18113,19121,23311,24113,24311,27311,31651,32129,
%U A178328 32221,34171,38131,41213,47231,49183,53831,56831,111223,111421,111811,121279,123121,129151,141233,156271,157651,161171
%N A178328 Numbers k such that k^p-p is prime, where p is product of the digits of k.
%C A178328 2 is the only even term of this sequence. Large numbers corresponding to some terms are probable prime.
%e A178328 21^(2*1) - (2*1) is prime so 21 is in the sequence.
%t A178328 Do[p=Apply[Times, IntegerDigits[n]]; If[PrimeQ[n^p-p], Print[n]], {n, 54891}]
%t A178328 (* or *)
%t A178328 ppdQ[n_]:=Module[{p=Times@@IntegerDigits[n]},PrimeQ[n^p-p]]; Select[ Range[ 120000],ppdQ] (* _Harvey P. Dale_, Nov 12 2017 *)
%Y A178328 Cf. A007954, A178327.
%K A178328 base,nonn
%O A178328 1,1
%A A178328 _Farideh Firoozbakht_, May 29 2010
%E A178328 a(34)-a(37) from _Max Alekseyev_, Feb 19 2012
%E A178328 a(38)-a(44) from _Michael S. Branicky_, Jun 25 2023