

A145254


a(n) = the smallest positive integer that is noncoprime to n and has the same number of 1's in its binary representation as n.


4



2, 3, 2, 5, 3, 7, 2, 3, 5, 11, 3, 13, 7, 15, 2, 17, 3, 19, 5, 7, 11, 23, 3, 25, 13, 15, 7, 29, 15, 31, 2, 3, 6, 7, 3, 37, 14, 15, 5, 41, 7, 43, 11, 15, 23, 47, 3, 7, 14, 15, 13, 53, 15, 55, 7, 15, 29, 59, 15, 61, 31, 63, 2, 5, 3, 67, 6, 21, 7, 71, 3, 73, 14, 15, 14, 77, 15, 79, 5, 21, 14, 83
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OFFSET

2,1


LINKS

Michael De Vlieger, Table of n, a(n) for n = 2..16384


MATHEMATICA

Table[Function[k, SelectFirst[Range[2, n], And[! CoprimeQ[#, n], DigitCount[#, 2, 1] == k] &]]@ DigitCount[n, 2, 1], {n, 2, 83}] (* Michael De Vlieger, Oct 26 2017 *)


PROG

(PARI) a(n) = {my(k = 1, hn = hammingweight(n)); while ((hammingweight(k) != hn)  (gcd(n, k) == 1), k++); k; } \\ Michel Marcus, Oct 27 2017


CROSSREFS

Cf. A145255, A145256, A145257.
Sequence in context: A006530 A102095 A109395 * A163457 A285708 A072593
Adjacent sequences: A145251 A145252 A145253 * A145255 A145256 A145257


KEYWORD

base,nonn,look


AUTHOR

Leroy Quet, Oct 05 2008


EXTENSIONS

Extended by Ray Chandler, Nov 03 2008


STATUS

approved



