OFFSET
0,3
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = A054893(4*n). - Vaclav Kotesovec, May 28 2014
G.f.: (1/(1 - x))*Sum_{k>=0} x^(4^k)/(1 - x^(4^k)). - Ilya Gutkovskiy, Mar 15 2018
EXAMPLE
a(4) = 4 + floor(4/4) + floor(4/16) + floor(4/64) + ... = 5.
MATHEMATICA
Table[Sum[Floor[n/4^k], {k, 0, 1000}], {n, 0, 50}] (* G. C. Greubel, Oct 11 2017 *)
PROG
(Haskell)
import Data.List (unfoldr)
a087069 =
sum . unfoldr (\x -> if x == 0 then Nothing else Just (x, x `div` 4))
-- Reinhard Zumkeller, Apr 22 2011
(PARI) for(n=0, 50, print1(sum(k=0, 1000, floor(n/4^k)), ", ")) \\ G. C. Greubel, Oct 11 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Aug 07 2003
STATUS
approved