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.

A071042 Number of 0's in n-th row of triangle in A070886.

Original entry on oeis.org

0, 1, 3, 3, 7, 7, 9, 7, 15, 15, 17, 15, 21, 19, 21, 15, 31, 31, 33, 31, 37, 35, 37, 31, 45, 43, 45, 39, 49, 43, 45, 31, 63, 63, 65, 63, 69, 67, 69, 63, 77, 75, 77, 71, 81, 75, 77, 63, 93, 91, 93, 87, 97, 91, 93, 79, 105, 99, 101, 87, 105, 91, 93, 63, 127, 127, 129, 127
Offset: 0

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Author

Hans Havermann, May 26 2002

Keywords

Comments

Also (omitting initial 0) number of 1's in n-th row of triangle in A071038, that is, number of ON cells at generation n of CA defined by Rule 182.

References

  • S. Wolfram, A New Kind of Science, Wolfram Media, 2002; Chapter 3.

Crossrefs

Programs

  • Mathematica
    Map[Function[Apply[Plus, Flatten[#1]]],
    CellularAutomaton[182, {{1}, 0}, 100]] (* N. J. A. Sloane, Feb 17 2015 *)
  • PARI
    a(n)=2*n-2^hammingweight(n)+1; \\ Altug Alkan, Dec 05 2015

Formula

a(n) = 2n + 1 - A001316(n) = n + A048967(n).
a(2n) = a(n) + 2n, a(2n+1) = 2a(n) + 1. - Ralf Stephan, Oct 07 2003