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 A133978 #11 Mar 23 2021 15:41:35
%S A133978 378997,777643,3127979,3127997,3136607,3173761,3374729,3377999,
%T A133978 3759263,3774161,3791387,3943967,7342469,7521641,7540541,7767709
%N A133978 Home primes whose homeliness is 12.
%C A133978 Number of terms < 10^n: 0, 0, 0, 0, 0, 2, 16, ... .
%t A133978 lst = {}; f[n_] := FromDigits@ Flatten[ IntegerDigits@ Table[ #[[1]], {#[[2]]}] & /@ FactorInteger@n, 2]; h[n_] := NestWhileList[f@# &, n, !PrimeQ@# &, 1, 28]; Do[p = h[n][[ -1]]; If[ PrimeQ@p && p < 10^7 && p != n, Print[{n, p}]; AppendTo[lst, p]], {n, 2, 1000}];
%t A133978 d = 12 - 2; lsu = {}; Do[ If[ lst[[n]] == lst[[n + d]] && lst[[n - 1]] != lst[[n]] && lst[[n]] != lst[[n + d + 1]], AppendTo[lsu, lst[[n]]]], {n, 188004 - d - 1}]; Take[Union@ lsu, 31]
%Y A133978 Cf. A037274, A118756, A133977, A133956, A133957, A133958, A133960, A133962, A133964, A133966, A133968, A133970, A133972, A133974, A133976.
%K A133978 nonn,base,more
%O A133978 1,1
%A A133978 _Robert G. Wilson v_, Sep 30 2007