A277335 - OEIS

A277335

Fibbinary numbers multiplied by three: a(n) = 3*A003714(n); Numbers where all 1-bits occur in runs of even length.

0, 3, 6, 12, 15, 24, 27, 30, 48, 51, 54, 60, 63, 96, 99, 102, 108, 111, 120, 123, 126, 192, 195, 198, 204, 207, 216, 219, 222, 240, 243, 246, 252, 255, 384, 387, 390, 396, 399, 408, 411, 414, 432, 435, 438, 444, 447, 480, 483, 486, 492, 495, 504, 507, 510, 768, 771, 774, 780, 783, 792, 795, 798, 816, 819, 822, 828, 831, 864, 867, 870, 876, 879, 888

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

The positive entries are the viabin numbers of integer partitions into even parts. The viabin number of an integer partition is defined in the following way. Consider the southeast border of the Ferrers board of the integer partition and consider the binary number obtained by replacing each east step with 1 and each north step, except the last one, with 0. The corresponding decimal form is, by definition, the viabin number of the given integer partition. "Viabin" is coined from "via binary". For example, consider the integer partition [6,4,4,2]. The southeast border of its Ferrers board yields 110110011, leading to the viabin number 435 (a term of the sequence). - Emeric Deutsch, Sep 11 2017

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..17711

Index entries for sequences related to binary expansion of n

FORMULA

a(n) = 3*A003714(n).

MATHEMATICA

3 Select[Range[300], BitAnd[#, 2 #]==0 &] (* Vincenzo Librandi, Sep 12 2017 *)

PROG

(Scheme) (define (A277335 n) (* 3 (A003714 n)))

CROSSREFS

Cf. A003714.

Positions of odd terms in A106737.