A161396 a(n) = the smallest positive integer that contains the same number of 1's as n when a(n) and n are written in binary, is not coprime to n, and is not a divisor of n.

4, 6, 8, 10, 9, 14, 16, 6, 6, 22, 9, 26, 21, 27, 32, 34, 10, 38, 6, 14, 14, 46, 9, 35, 14, 15, 21, 58, 27, 62, 64, 6, 6, 14, 10, 74, 14, 15, 6, 82, 22, 86, 14, 27, 30, 94, 9, 14, 14, 15, 14, 106, 15, 110, 21, 15, 30, 118, 27, 122, 93, 111, 128, 10, 9, 134, 6

Offset

2,1

Links

Rémy Sigrist, Table of n, a(n) for n = 2..10000

Example

6_10 (6 in decimal) is 110_2 (110 in binary). 9_10 = 1001_2, which contains the same number of ones in the binary expansion. 9 isn't coprime to 6; they share prime factor 3 and 9 isn't a divisor of 6. No positive integer less than 9 has these properties. Therefore, a(6) = 9.

Crossrefs

Cf. A145256, A161397

Sequence in context: A191488 A162600 A071537 * A145256 A087789 A071830

Adjacent sequences: A161393 A161394 A161395 * A161397 A161398 A161399

Keyword

base,nonn

Author

Leroy Quet, Jun 09 2009

Extensions

Offset corrected and more terms from Rémy Sigrist, Apr 15 2017

Status

approved