login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A227326
a(2n) = 2a(n)+2^(2n), a(2n+1) = 2^(2n+1), a(0)=0.
1
0, 2, 8, 8, 32, 32, 80, 128, 320, 512, 1088, 2048, 4256, 8192, 16640, 32768, 66176, 131072, 263168, 524288, 1050752, 2097152, 4198400, 8388608, 16785728, 33554432, 67125248, 134217728, 268468736, 536870912, 1073807360, 2147483648, 4295099648, 8589934592
OFFSET
0,2
COMMENTS
Simplest sequence of form a(2n)=c*a(n)+f(n), a(2n+1)=g(n) that cannot be easily expressed as a function of A007814(n).
LINKS
FORMULA
a(n) = sum(k=0..A007814(n), 2^(k+n/2^k) ).
PROG
(PARI) a(n)=sum(k=0, valuation(n, 2), 2^(k+n/2^k))
(PARI) a(n)=if(n<1, 0, if(n%2==0, 2*a(n/2)+2^n, 2^n))
(Haskell)
import Data.List (transpose)
a227326 n = a227326_list !! n
a227326_list = 0 : xs where
xs = concat $ transpose
[a004171_list, zipWith (+) (tail a000302_list) (map (* 2) xs)]
-- Reinhard Zumkeller, Jul 08 2013
CROSSREFS
Sequence in context: A180825 A230708 A230739 * A323852 A064231 A181130
KEYWORD
nonn,easy
AUTHOR
Ralf Stephan, Jul 07 2013
STATUS
approved