A155905 Numbers n such that it is possible to append a single digit to the end of 2^n to make it prime.

0, 1, 2, 3, 4, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 24, 25, 27, 30, 31, 33, 36, 38, 42, 43, 46, 49, 50, 51, 54, 55, 57, 58, 60, 64, 65, 73, 74, 84, 93, 106, 108, 123, 126, 129, 139, 150, 162, 183, 187, 196, 198, 220, 271, 273, 279, 301, 312, 379, 392

Offset

1,3

Comments

Expected to be infinite because the harmonic series diverges.

Links

Table of n, a(n) for n=1..64.

Example

For example 641 and 1283 are prime so 6 and 7 are in the sequence respectively.

Crossrefs

Sequence in context: A057519 A337659 A373041 * A375928 A287531 A047518

Adjacent sequences: A155902 A155903 A155904 * A155906 A155907 A155908

Keyword

nonn,base

Author

Dmitry Kamenetsky, Jan 30 2009

Status

approved