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A078839 Numbers n such that the binary expansion of 3^n has the same number of 0's and 1's. 0
2, 12, 69, 73, 150, 184, 252, 328, 339, 464, 483, 541, 729, 747, 758, 763, 1014, 1047, 1090, 1094, 1158, 1264, 1359, 1601, 1679, 1693, 1698, 1780, 2368, 2641, 2815, 3292, 3393, 3606, 3682, 3857, 3909, 3919, 3963, 4087, 4111, 4289, 4314, 5017, 5398, 5466 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Does the limit of a(n)/n^2 as n -> infinity exist?

LINKS

Table of n, a(n) for n=1..46.

MATHEMATICA

balanced[n_] := Module[{d=IntegerDigits[n, 2]}, Plus@@d==Length[d]/2]; Select[Range[0, 5500], balanced[3^# ]&]

PROG

(PARI) is(n)=hammingweight(n=3^n)==hammingweight(bitneg(n, #binary(n))) \\ Charles R Greathouse IV, Mar 29 2013

CROSSREFS

Cf. A031443, A011754.

Sequence in context: A128103 A329789 A245854 * A243771 A026306 A116398

Adjacent sequences:  A078836 A078837 A078838 * A078840 A078841 A078842

KEYWORD

nonn,base

AUTHOR

Benoit Cloitre, Dec 06 2002

STATUS

approved

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Last modified October 18 06:01 EDT 2021. Contains 348065 sequences. (Running on oeis4.)