login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A163617 a(2*n) = 2*a(n), a(2*n + 1) = 2*a(n) + 2 + (-1)^n, for all n in Z. 15
0, 3, 6, 7, 12, 15, 14, 15, 24, 27, 30, 31, 28, 31, 30, 31, 48, 51, 54, 55, 60, 63, 62, 63, 56, 59, 62, 63, 60, 63, 62, 63, 96, 99, 102, 103, 108, 111, 110, 111, 120, 123, 126, 127, 124, 127, 126, 127, 112, 115, 118, 119, 124, 127, 126, 127, 120, 123, 126, 127, 124, 127, 126 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Fibbinary numbers (A003714) give all integers n>=0 for which a(n) = 3*n.

From Antti Karttunen, Feb 21 2016: (Start)

Fibbinary numbers give also all integers n >= 0 for which a(n) = A048724(n).

Note that there are also other multiples of three in the sequence, like for example A163617(99) = 231 ("11100111" in binary) = 3*77, while 77 ("1001101" in binary) is not included in A003714. Note that 99 is "1100011" in binary.

(End)

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = -A163618(-n) for all n in ZZ.

Conjecture: a(n) = A003188(n) + (6*n+1-(-1)^n)/4. - Velin Yanev, Dec 17 2016

EXAMPLE

G.f. = 3*x + 6*x^2 + 7*x^3 + 12*x^4 + 15*x^5 + 14*x^6 + 15*x^7 + 24*x^8 + 27*x^9 + ...

MAPLE

A163617 := n -> Bits:-Or(2*n, n):

seq(A163617(n), n=0..62); # Peter Luschny, Sep 23 2019

MATHEMATICA

Table[BitOr[n, 2*n], {n, 0, 100}] (* Vladimir Joseph Stephan Orlovsky, Jul 19 2011 *)

PROG

(PARI) {a(n) = bitor(n, n<<1)};

(PARI) {a(n) = if( n==0 || n==-1, n, 2 * a(n \ 2) + (n%2) * (2 + (-1)^(n \ 2)))};

(Haskell)

import Data.Bits ((.|.), shiftL)

a163617 n = n .|. shiftL n 1 :: Integer

-- Reinhard Zumkeller, Mar 06 2013

(Scheme) (define (A163617 n) (A003986bi n (+ n n))) ;; Here A003986bi implements dyadic bitwise-OR operation (see A003986) - Antti Karttunen, Feb 21 2016

CROSSREFS

Cf. A003986, A048724, A213370, A163618.

Cf. also A269161.

Sequence in context: A226228 A269174 A161903 * A189634 A047705 A309839

Adjacent sequences:  A163614 A163615 A163616 * A163618 A163619 A163620

KEYWORD

nonn

AUTHOR

Michael Somos, Aug 01 2009

EXTENSIONS

Comment about Fibbinary numbers rephrased by Antti Karttunen, Feb 21 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 15 03:48 EST 2019. Contains 329990 sequences. (Running on oeis4.)