A350319 Totient numbers k such that 9*k is a nontotient.

1, 10, 46, 66, 78, 106, 126, 138, 150, 166, 178, 190, 210, 226, 262, 268, 270, 306, 346, 358, 366, 372, 378, 382, 418, 430, 442, 466, 478, 490, 506, 522, 546, 570, 586, 598, 606, 630, 646, 676, 682, 718, 726, 738, 750, 786, 810, 822, 826, 838, 882, 886, 906

Offset

1,2

Links

Table of n, a(n) for n=1..53.

Example

10 is a term since 10 = phi(11) = phi(22), but phi(n) = 9*10 = 90 has no solution.
46 is a term since 46 = phi(47) = phi(94), but phi(n) = 9*46 = 414 has no solution.

Prog

(PARI) isA350319(n) = istotient(n) && !istotient(9*n)

Crossrefs

Totient numbers k such that m*k is a nontotient: A350316 (m=3), A350317 (m=5), A350318 (m=7), this sequence (m=9), A350320 (m=10), A350321 (m=14).

Cf. A002202, A005277.

Sequence in context: A044112 A073248 A044493 * A279092 A007941 A007940

Adjacent sequences: A350316 A350317 A350318 * A350320 A350321 A350322

Keyword

nonn

Author

Jianing Song, Dec 24 2021

Status

approved