A053568 Totients of nontotient numbers.

2, 4, 6, 6, 10, 12, 6, 8, 16, 18, 12, 22, 20, 12, 18, 28, 30, 20, 16, 24, 36, 18, 24, 40, 42, 24, 46, 42, 20, 32, 52, 40, 36, 58, 60, 30, 36, 48, 66, 32, 44, 70, 72, 36, 40, 36, 60, 78, 54, 82, 64, 42, 56, 88, 24, 72, 60, 46, 72, 96, 42, 60, 100, 102, 48, 106

Offset

1,1

Comments

See comment at analogous sequence A053474.

Links

Table of n, a(n) for n=1..66.

Formula

a(n) = A000010(A007617(n)).

Example

If n=19 then no number x such that phi(x) = n exists; however, phi(19) = 18;
n=27 is also a nontotient number whose totient is 18.

Prog

(PARI) lista(nn) = for (n=1, nn, if (!istotient(n), print1(eulerphi(n), ", "))); \\ Michel Marcus, Nov 20 2017

Crossrefs

Cf. A000010, A007617.

Sequence in context: A061228 A070229 A248835 * A037225 A060685 A073353

Adjacent sequences: A053565 A053566 A053567 * A053569 A053570 A053571

Keyword

nonn

Author

Labos Elemer, Jan 17 2000

Status

approved