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 A096504 #16 Jun 06 2024 03:49:23
%S A096504 1,1,2,2,4,2,6,4,6,4,4,6,8,8,6,8,22,8,8,22,66,44,88,44,88,66,44,88,88,
%T A096504 222,88,88,222,444,444,888,888,444,888,888,888,888,888,888,444444,
%U A096504 666666,444444,888888,888888,666666,888888,888888,888888,888888,888888
%N A096504 Euler-phi applied to A096503 results in these decimal repdigits.
%H A096504 Amiram Eldar, <a href="/A096504/b096504.txt">Table of n, a(n) for n = 1..182</a> (calculated using the b-file at A096503)
%F A096504 a(n) = A000010(A096503(n)).
%e A096504 a(60) = A000010(A096503(60)) = A000010(88888892) = 44444444.
%e A096504 Regular solutions: if p = repdigit + 1 is prime, then phi(p) = repdigit.
%o A096504 (PARI) lista(nn) = {for (n= 1, nn, phin = eulerphi(n); d = digits(e=eulerphi(n)); if (vecmin(d) == vecmax(d), print1(e, ", ")););} \\ _Michel Marcus_, Sep 07 2014
%Y A096504 Cf. A000010, A010785, A096503, A096505.
%K A096504 base,nonn
%O A096504 1,3
%A A096504 _Labos Elemer_, Jul 12 2004