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A145257 a(n) is the smallest integer > n that is non-coprime to n and has the same number of 0's in its binary representation as n has. 5
6, 15, 10, 30, 14, 63, 18, 12, 12, 55, 21, 247, 30, 63, 34, 85, 20, 57, 24, 28, 26, 253, 38, 45, 28, 30, 46, 1015, 55, 1023, 66, 36, 36, 42, 40, 185, 42, 45, 48, 205, 44, 215, 50, 51, 54, 14335, 69, 56, 52, 54, 56, 159, 57, 95, 77, 60, 60, 767, 87, 4087, 126, 255, 130, 80 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

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

Rémy Sigrist, PARI program for A145257

MATHEMATICA

a[n_] := Block[{}, i = n + 1; While[GCD[i, n] == 1 || Not[DigitCount[n, 2, 0] == DigitCount[i, 2, 0]], i++ ]; i]; Table[a[n], {n, 2, 100}] (* Stefan Steinerberger, Oct 17 2008 *)

PROG

(PARI) See Links section.

(PARI) a(n) = {my(m = n+1, nb = #binary(n) - hammingweight(n)); while (!((gcd(m, n) > 1) && (nb == #binary(m) - hammingweight(m))), m++); m; } \\ Michel Marcus, Feb 06 2020

(MAGMA) a:=[]; for n in [2..70] do k:=n+1; while Gcd(n, k) eq 1 or  Multiplicity(Intseq(n, 2), 0) ne  Multiplicity(Intseq(k, 2), 0) do k:=k+1; end while; Append(~a, k); end for; a; // Marius A. Burtea, Feb 06 2020

CROSSREFS

Cf. A023416 (number of 0's in binary expansion of n).

Cf. A140977, A145254, A145255, A145256.

Sequence in context: A240990 A215739 A161397 * A245200 A070555 A265388

Adjacent sequences:  A145254 A145255 A145256 * A145258 A145259 A145260

KEYWORD

base,nonn,changed

AUTHOR

Leroy Quet, Oct 05 2008

EXTENSIONS

More terms from Stefan Steinerberger, Oct 17 2008

a(58)-a(64) from Ray Chandler, Jun 20 2009

STATUS

approved

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Last modified February 20 13:40 EST 2020. Contains 332077 sequences. (Running on oeis4.)