A072106 The number of nontotients (even and odd) in the reduced residue system of n.

0, 0, 0, 1, 1, 1, 2, 3, 2, 3, 4, 3, 5, 5, 4, 7, 8, 5, 9, 7, 5, 9, 11, 7, 10, 11, 10, 11, 15, 7, 16, 15, 11, 15, 13, 11, 20, 17, 14, 15, 23, 11, 24, 19, 15, 21, 26, 15, 23, 19, 19, 23, 30, 17, 23, 23, 21, 27, 33, 15, 34, 29, 22, 31, 27, 19, 38, 31, 28, 23, 41, 23, 42, 35, 26, 35, 37

Offset

1,7

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

For n=113: the reduced residue system consists of 112 numbers: Card[OddNonTotients(113)] = 56 - 1, EvenNonTotients = {14,26,34,38,50,62,68,74,76,86,90,94,98}, i.e., 13 terms, therefore a(113) = 56 - 1 + 13 = 68.

Prog

(PARI) a(n) = sum(k = 1, n, gcd(n, k) == 1 && !istotient(k)); \\ Amiram Eldar, Nov 07 2024

Crossrefs

Cf. A000010, A002202, A005277, A037225, A072451, A072455.

Sequence in context: A020986 A326820 A095161 * A124524 A303543 A124525

Adjacent sequences: A072103 A072104 A072105 * A072107 A072108 A072109

Keyword

nonn

Author

Labos Elemer, Jun 19 2002

Status

approved