OFFSET
1,1
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..4095
FORMULA
a(2n) = 2a(n), a(2n+1) = 2a(n) + 1 + 5*[n==0].
a(2^m+k) = 6*2^m + k, m >= 0, 0 <= k < 2^m. - Yosu Yurramendi, Aug 08 2016
EXAMPLE
26 in binary is 11010, so 26 is in sequence.
MATHEMATICA
w = {1, 1, 0}; Select[Range[5, 213], If[# < 2^(Length@ w - 1), True, Take[IntegerDigits[#, 2], Length@ w] == w] &] (* or *)
Table[n + 5*2^Floor@ Log2@ n, {n, 53}] (* Michael De Vlieger, Aug 10 2016 *)
PROG
(PARI) a(n)=n+5*2^floor(log(n)/log(2))
(Haskell)
import Data.List (transpose)
a004758 n = a004758_list !! (n-1)
a004758_list = 6 : concat (transpose [zs, map (+ 1) zs])
where zs = map (* 2) a004758_list
-- Reinhard Zumkeller, Dec 03 2015
(Python)
def A004758(n): return n+(5<<n.bit_length()-1) # Chai Wah Wu, Jul 13 2022
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
Edited by Ralf Stephan, Oct 12 2003
STATUS
approved