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.

A284882 Positions of -1 in A284881.

Original entry on oeis.org

2, 5, 8, 11, 15, 18, 20, 23, 26, 29, 33, 36, 38, 41, 45, 48, 50, 53, 56, 59, 62, 65, 69, 72, 74, 77, 80, 83, 87, 90, 92, 95, 99, 102, 104, 107, 110, 113, 116, 119, 123, 126, 128, 131, 135, 138, 140, 143, 146, 149, 152, 155, 159, 162, 164, 167, 170, 173, 177
Offset: 1

Views

Author

Clark Kimberling, Apr 16 2017

Keywords

Comments

This sequence and A284883 and A284884 form a partition of the positive integers. For n>=1, we have 3n-a(n) in {0,1}, 3*n+1-A284883(n) in {0,1,2,3}, and 3*n-1-A284884(n) in {0,1,2}.
A284881 = (1,-1,1,0,-1,0,1,-1,1,0,-1,0,1,0,...); thus
A284882 = (2,5,8,11,15,18,...)
A284883 = (4,6,10,12,14,16,...)
A284884 = (1,3,7,9,13,17,...).

Crossrefs

Programs

  • Mathematica
    s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0, 1, 1, 0}}] &, {0}, 6] (* A284878 *)
    d = Differences[s]  (* A284881 *)
    Flatten[Position[d, -1]] (* A284882 *)
    d2 = Flatten[Position[d, 0]]  (* A284883 *)
    Flatten[Position[d, 1]]  (* A284884 *)
    d2/2  (* A284885 *)