A067233 Numbers n such that phi(3n+1) = sigma(n).

3, 21, 23, 27, 30, 65, 69, 95, 133, 143, 203, 253, 264, 413, 447, 537, 618, 667, 672, 715, 863, 897, 1092, 1122, 1221, 1265, 1343, 1824, 2367, 2757, 2765, 3009, 3231, 3471, 3605, 3683, 3741, 4088, 4195, 4578, 5838, 6295, 6533, 6747, 7689, 7701, 9548

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Prog

(PARI) isok(n) = eulerphi(3*n+1) == sigma(n); \\ Michel Marcus, Nov 21 2013

Crossrefs

Cf. A000010, A000203, A067232.

Sequence in context: A279842 A043081 A091675 * A007648 A273481 A050586

Adjacent sequences: A067230 A067231 A067232 * A067234 A067235 A067236

Keyword

nonn

Author

Benoit Cloitre, Feb 20 2002

Status

approved