cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

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

Original entry on oeis.org

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

Views

Author

Jianing Song, Dec 24 2021

Keywords

Examples

			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.

Links

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.

Programs

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

A350317 Totient numbers k such that 5*k is a nontotient.

Original entry on oeis.org

1, 10, 18, 46, 58, 70, 78, 82, 102, 106, 110, 130, 136, 148, 166, 178, 190, 220, 222, 226, 238, 250, 262, 268, 270, 282, 292, 310, 316, 330, 342, 346, 358, 378, 382, 418, 430, 438, 442, 466, 478, 486, 490, 498, 502, 508, 522, 556, 562, 568, 586, 598, 606, 618
Offset: 1

Views

Author

Jianing Song, Dec 24 2021

Keywords

Examples

			10 is a term since 10 = phi(11) = phi(22), but phi(n) = 5*10 = 50 has no solution.
18 is a term since 18 = phi(19) = phi(27) = phi(38) = phi(54), but phi(n) = 5*18 = 90 has no solution.

Links

Crossrefs

Totient numbers k such that m*k is a nontotient: A350316 (m=3), this sequence (m=5), A350318 (m=7), A350319 (m=9), A350320 (m=10), A350321 (m=14).
Cf. A002202, A005277.

Programs

  • PARI
    isA350317(n) = istotient(n) && !istotient(5*n)

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

Original entry on oeis.org

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

Views

Author

Jianing Song, Dec 24 2021

Keywords

Examples

			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.

Links

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.

Programs

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

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

Original entry on oeis.org

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

Views

Author

Jianing Song, Dec 24 2021

Keywords

Examples

			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.

Links

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.

Programs

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

A350321 Totient numbers k such that 14*k is a nontotient.

Original entry on oeis.org

1, 22, 46, 52, 82, 148, 172, 178, 190, 250, 262, 292, 310, 358, 366, 382, 388, 442, 466, 490, 502, 506, 556, 562, 568, 586, 598, 652, 658, 682, 718, 742, 772, 822, 852, 862, 910, 946, 982, 1090, 1102, 1150, 1162, 1186, 1210, 1222, 1278, 1282, 1306, 1366, 1372
Offset: 1

Views

Author

Jianing Song, Dec 24 2021

Keywords

Comments

14 is the smallest even nontotient.

Examples

			52 is a term since 52 = phi(53) = phi(106), but phi(n) = 14*52 = 728 has no solution.
172 is a term since 172 = phi(173) = phi(346), but phi(n) = 14*172 = 2408 has no solution.

Links

Crossrefs

Totient numbers k such that m*k is a nontotient: A350316 (m=3), A350317 (m=5), A350318 (m=7), A350319 (m=9), A350320 (m=10), this sequence (m=14).
Cf. A002202, A005277.

Programs

  • PARI
    isA350321(n) = istotient(n) && !istotient(14*n)
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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