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.

A279318 Permutation of the nonnegative integers [6k+3, 6k+2, 6k+1, 6k, 6k+5, 6k+4].

Original entry on oeis.org

3, 2, 1, 0, 5, 4, 9, 8, 7, 6, 11, 10, 15, 14, 13, 12, 17, 16, 21, 20, 19, 18, 23, 22, 27, 26, 25, 24, 29, 28, 33, 32, 31, 30, 35, 34, 39, 38, 37, 36, 41, 40, 45, 44, 43, 42, 47, 46, 51, 50, 49, 48, 53, 52, 57, 56, 55, 54, 59, 58, 63, 62, 61, 60, 65, 64, 69
Offset: 0

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Author

Wesley Ivan Hurt, Dec 09 2016

Keywords

Crossrefs

Programs

  • Magma
    &cat[[6*k+3, 6*k+2, 6*k+1, 6*k, 6*k+5, 6*k+4] : k in [0..20]];
  • Maple
    f:= gfun:-rectoproc({a(n+7)-a(n+6)-a(n+1)+a(n)=0, seq(a(i)=[3, 2, 1, 0, 5, 4, 9][i+1],i=0..6)},a(n),remember):
    map(f, [$0..100]); # Robert Israel, Dec 13 2016
  • Mathematica
    Reverse/@TakeDrop[#,4]&/@Partition[Range[0,80],6]//Flatten (* Requires Mathematica version 10 or later *) (* or *) LinearRecurrence[ {1,0,0,0,0,1,-1},{3,2,1,0,5,4,9},80] (* Harvey P. Dale, Dec 16 2017 *)

Formula

a(n) = 1 + abs(n - 2 - 6*round((2n - 3)/6)) for n > 3.
G.f.: (3-x-x^2-x^3+5*x^4-x^5+2*x^6)/(1-x-x^6+x^7). - Robert Israel, Dec 13 2016
Sum_{n>=0, n!=3} (-1)^n/a(n) = log(2) (A002162). - Amiram Eldar, Dec 25 2023