A096504 - OEIS

%I #16 Jun 06 2024 03:49:23

%S 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 222,88,88,222,444,444,888,888,444,888,888,888,888,888,888,444444,

%U 666666,444444,888888,888888,666666,888888,888888,888888,888888,888888

%N Euler-phi applied to A096503 results in these decimal repdigits.

%H 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 a(n) = A000010(A096503(n)).

%e a(60) = A000010(A096503(60)) = A000010(88888892) = 44444444.

%e Regular solutions: if p = repdigit + 1 is prime, then phi(p) = repdigit.

%o (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 Cf. A000010, A010785, A096503, A096505.

%K base,nonn

%O 1,3

%A _Labos Elemer_, Jul 12 2004