The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A094120 a(n) = Sum_{k=1..n} Sum_{i=1..k} (-2)^valuation(i,2). 1
 0, 1, 0, 0, 4, 9, 12, 16, 12, 9, 4, 0, 0, 1, 0, 0, 16, 33, 48, 64, 84, 105, 124, 144, 156, 169, 180, 192, 208, 225, 240, 256, 240, 225, 208, 192, 180, 169, 156, 144, 124, 105, 84, 64, 48, 33, 16, 0, 0, 1, 0, 0, 4, 9, 12, 16, 12, 9, 4, 0, 0, 1, 0, 0, 64, 129, 192, 256, 324, 393 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 LINKS Michael De Vlieger, Table of n, a(n) for n = 0..10000 Hsien-Kuei Hwang, Svante Janson, and Tsung-Hsi Tsai, Identities and periodic oscillations of divide-and-conquer recurrences splitting at half, arXiv:2210.10968 [cs.DS], 2022, pp. 49-51. MATHEMATICA {0}~Join~Accumulate@ Accumulate@ Array[(-2)^IntegerExponent[#, 2] &, 69] (* Michael De Vlieger, Oct 30 2022 *) PROG (PARI) a(n)=sum(k=1, n, sum(i=1, k, (-2)^valuation(i, 2))) CROSSREFS Cf. A006519. Sequence in context: A312853 A312854 A010386 * A066423 A355571 A072498 Adjacent sequences: A094117 A094118 A094119 * A094121 A094122 A094123 KEYWORD nonn AUTHOR Benoit Cloitre, May 03 2004 STATUS approved

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

Last modified May 19 14:35 EDT 2024. Contains 372698 sequences. (Running on oeis4.)