A002020 -id:A002020 - cp's OEIS frontend

A058825 Numbers which are both totients and cototients.

1, 2, 4, 6, 8, 12, 16, 18, 20, 22, 24, 28, 30, 32, 36, 40, 42, 44, 46, 48, 54, 56, 60, 64, 66, 70, 72, 78, 80, 82, 84, 88, 92, 96, 102, 104, 106, 108, 110, 112, 120, 126, 128, 132, 136, 138, 140, 144, 148, 150, 156, 160, 162, 164, 166, 168, 176, 178, 180, 184, 190

Offset: 1

Labos Elemer, Jan 04 2001

nonn

			24 is here because 24 = phi(72) = 44-phi(44) = 44-20 = cototient(44).

Donovan Johnson, Table of n, a(n) for n = 1..10000

Cf. A000010, A051953, A005277, A005278, A002020, A058763.

Intersection(A002202, A051953).

Offset corrected by Donovan Johnson, Nov 17 2013

A058826 Even cototient numbers which are nontotients.

Original entry on oeis.org

14, 38, 62, 68, 74, 76, 90, 94, 98, 114, 118, 124, 142, 152, 158, 174, 182, 188, 194, 214, 230, 234, 236, 242, 246, 248, 254, 258, 278, 284, 286, 302, 304, 308, 314, 318, 322, 334, 338, 350, 354, 364, 370, 374, 376, 390, 398, 402, 406, 410, 414, 422, 426

Offset: 1

Labos Elemer, Jan 04 2001

nonn

			14 is a nontotient number but it is cototient of 26: 14 = 26 - phi(26).

Donovan Johnson, Table of n, a(n) for n = 1..10000

Cf. A000010, A051953, A005277, A005278, A002020, A058763, A058817.

Intersection(A058817, A005277).

A058827 Totients which are not cototients.

Original entry on oeis.org

10, 52, 58, 100, 116, 130, 172, 222, 232, 260, 268, 292, 310, 344, 346, 366, 372, 466, 490, 520, 536, 546, 562, 580, 584, 652, 688, 732, 772, 786, 808, 906, 932, 940, 980, 1018, 1038, 1068, 1072, 1108, 1160, 1168, 1192, 1210, 1300, 1332, 1360, 1372, 1376

Offset: 1

Labos Elemer, Jan 04 2001

nonn

			10, the smallest noncototient number, is the totient of 11.

Donovan Johnson, Table of n, a(n) for n = 1..10000

Cf. A000010, A051953, A005277, A005278, A002020, A058763.

Intersection(noncototients=A005278, A002202=totients).

More terms from Don Reble, Nov 28 2001

Offset corrected by Donovan Johnson, Nov 17 2013

cp's OEIS Frontend

A058825 Numbers which are both totients and cototients.

Views

Author

Keywords

Examples

Links

Crossrefs

Formula

Extensions

A058826 Even cototient numbers which are nontotients.

Views

Author

Keywords

Examples

Links

Crossrefs

Formula

A058827 Totients which are not cototients.

Views

Author

Keywords

Examples

Links

Crossrefs

Formula

Extensions