cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A197911 Representable by A001045 (Jacobsthal sequence). Complement of A003158.

Original entry on oeis.org

0, 1, 3, 4, 5, 6, 8, 9, 11, 12, 14, 15, 16, 17, 19, 20, 21, 22, 24, 25, 26, 27, 29, 30, 32, 33, 35, 36, 37, 38, 40, 41, 43, 44, 46, 47, 48, 49, 51, 52, 54, 55, 57, 58, 59, 60, 62, 63, 64, 65, 67, 68, 69, 70, 72, 73, 75, 76, 78, 79, 80, 81, 83, 84, 85, 86, 88
Offset: 0

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Author

Philippe Deléham, Oct 19 2011

Keywords

Comments

a(n) modulo 2 is the Prouhet-Thue-Morse sequence A010060.
The sequence of Jacobsthal numbers A001045 begins [1, 1, 3, 5, 11, 21, ...] with two occurrences of the term 1. Allowing for this, we find that the numbers representable as a sum of distinct Jacobsthal numbers form A050292. - Peter Bala, Feb 02 2013
Partial sums of A056832. - Reinhard Zumkeller, Jul 29 2014

Crossrefs

Programs

  • Haskell
    a197911 n = a197911_list !! n
    a197911_list = scanl (+) 0 a056832_list
    -- Reinhard Zumkeller, Jul 29 2014
    
  • Python
    def A197911(n): return n+sum((~(i+1)&i).bit_length()&1 for i in range(n)) # Chai Wah Wu, Jan 09 2023

Formula

a(n) = Sum_{k>=0} A030308(n,k)*A001045(k+2).