A350318 Totient numbers k such that 7*k is a nontotient.

1, 2, 22, 44, 46, 52, 58, 82, 92, 102, 104, 110, 148, 162, 164, 172, 178, 190, 198, 222, 250, 262, 270, 282, 292, 296, 310, 342, 344, 356, 358, 366, 380, 382, 388, 442, 462, 466, 486, 490, 498, 500, 502, 506, 522, 524, 556, 562, 568, 570, 584, 586, 598, 620

Offset

1,2

Links

Table of n, a(n) for n=1..54.

Example

44 is a term since 44 = phi(69) = phi(92) = phi(138), but phi(n) = 7*44 = 308 has no solution.
52 is a term since 52 = phi(53) = phi(106), but phi(n) = 7*52 = 364 has no solution.

Prog

(PARI) isA350318(n) = istotient(n) && !istotient(7*n)

Crossrefs

Totient numbers k such that m*k is a nontotient: A350316 (m=3), A350317 (m=5), this sequence (m=7), A350319 (m=9), A350320 (m=10), A350321 (m=14).

Cf. A002202, A005277.

Sequence in context: A060108 A221762 A154798 * A080142 A364484 A306969

Adjacent sequences: A350315 A350316 A350317 * A350319 A350320 A350321

Keyword

nonn

Author

Jianing Song, Dec 24 2021

Status

approved