A145254 - OEIS

A145254

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

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: A102095 A331959 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