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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.
2
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
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
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Jun 09 2009
EXTENSIONS
Offset corrected and more terms from Rémy Sigrist, Apr 15 2017
STATUS
approved