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A135569 a(n) = S2(n)*2^n; where S2(n) is digit sum of n, n in binary notation. 1
0, 2, 4, 16, 16, 64, 128, 384, 256, 1024, 2048, 6144, 8192, 24576, 49152, 131072, 65536, 262144, 524288, 1572864, 2097152, 6291456, 12582912, 33554432, 33554432, 100663296, 201326592, 536870912, 805306368, 2147483648, 4294967296 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

For all n we have 2/n <= a(n+1)/a(n)<= 4. This holds because a(2^n -1)= n*2^(2^n -1); a(2^n) = 2^2^n; a(2^n +1) = 4*2^2^n.

a(n) = A000120(n)*2^n. - R. J. Mathar, Mar 03 2008

MAPLE

A000120 := proc(n) add(i, i=convert(n, base, 2)) ; end: A135569 := proc(n) A000120(n)*2^n ; end: seq(A135569(n), n=0..80) ; # R. J. Mathar, Mar 03 2008

MATHEMATICA

Table[DigitCount[n, 2, 1]*2^n, {n, 0, 25}] (* G. C. Greubel, Oct 19 2016 *)

CROSSREFS

Cf. A000120, A010060.

Sequence in context: A067846 A155893 A196202 * A210579 A217863 A186108

Adjacent sequences:  A135566 A135567 A135568 * A135570 A135571 A135572

KEYWORD

easy,nonn,base

AUTHOR

Ctibor O. Zizka, Feb 23 2008, Mar 03 2008

EXTENSIONS

Corrected and extended by R. J. Mathar, Mar 03 2008

STATUS

approved

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Last modified January 21 19:47 EST 2019. Contains 319350 sequences. (Running on oeis4.)