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.

A356133 Complement of A026430.

Original entry on oeis.org

2, 4, 7, 11, 13, 17, 20, 22, 25, 29, 32, 34, 38, 40, 43, 47, 49, 53, 56, 58, 62, 64, 67, 71, 74, 76, 79, 83, 85, 89, 92, 94, 97, 101, 104, 106, 110, 112, 115, 119, 122, 124, 127, 131, 133, 137, 140, 142, 146, 148, 151, 155, 157, 161, 164, 166, 169, 173, 176
Offset: 1

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Author

Clark Kimberling, Aug 04 2022

Keywords

Examples

			The partial sums of the Thue-Morse sequence A001285 = (1,2,2,1,2,1,1,...) are A026430 = (0,1,3,5,6,8,9,10,...), from which the missing positive integers are (2,4,7,11,...).
		

Crossrefs

Programs

  • Mathematica
    u = Accumulate[1 + ThueMorse /@ Range[0, 2^7]]; (* A026430 *)
    Complement[Range[Max[u]], u]  (* A356133 *)
  • PARI
    a(n) = 3*n - 1 - hammingweight(n-1)%2; \\ Kevin Ryde, Aug 04 2022
    
  • Python
    def A356133(n): return 3*n-(2 if (n-1).bit_count()&1 else 1) # Chai Wah Wu, Mar 01 2023

Formula

a(n) = 3n - A001285(n-1) for n >= 1.