A350316 Totient numbers k such that 3*k is a nontotient.

1, 30, 58, 78, 82, 106, 130, 138, 150, 172, 178, 198, 222, 226, 238, 268, 282, 316, 342, 358, 366, 378, 382, 388, 418, 438, 462, 478, 498, 502, 506, 508, 546, 562, 570, 598, 606, 618, 630, 642, 646, 652, 658, 682, 690, 718, 738, 742, 772, 786, 810, 826, 838

Offset

1,2

Links

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

Example

30 is a term since 30 = phi(31) = phi(62), but phi(n) = 3*30 = 90 has no solution.
58 is a term since 58 = phi(59) = phi(118), but phi(n) = 3*58 = 174 has no solution.

Prog

(PARI) isA350316(n) = istotient(n) && !istotient(3*n)

Crossrefs

Totient numbers k such that m*k is a nontotient: this sequence (m=3), A350317 (m=5), A350318 (m=7), A350319 (m=9), A350320 (m=10), A350321 (m=14).

Cf. A002202, A005277.

Sequence in context: A154599 A048451 A154796 * A248572 A248739 A004962

Adjacent sequences: A350313 A350314 A350315 * A350317 A350318 A350319

Keyword

nonn

Author

Jianing Song, Dec 24 2021

Status

approved