A096504 Euler-phi applied to A096503 results in these decimal repdigits.

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, 222, 88, 88, 222, 444, 444, 888, 888, 444, 888, 888, 888, 888, 888, 888, 444444, 666666, 444444, 888888, 888888, 666666, 888888, 888888, 888888, 888888, 888888

Offset: 1

Author

Labos Elemer, Jul 12 2004

Keywords

• base
• nonn

Examples

			a(60) = A000010(A096503(60)) = A000010(88888892) = 44444444.
Regular solutions: if p = repdigit + 1 is prime, then phi(p) = repdigit.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..182 (calculated using the b-file at A096503)

Crossrefs

Cf. A000010, A010785, A096503, A096505.

Programs

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

Formula

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