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.

A298307 Start with a(0) = 1 and add at step n >= 0 the term 1 at position floor(4*(n+a(n))/3).

Original entry on oeis.org

1, 1, 1, 0, 2, 0, 1, 0, 1, 2, 0, 0, 1, 1, 2, 0, 0, 1, 1, 0, 1, 2, 0, 0, 1, 2, 0, 0, 1, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 0, 1, 1, 2, 0, 0, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 0, 1, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 1, 2, 0, 0, 1, 1, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 1, 2, 0, 0, 1, 1, 2, 0, 0, 1, 1, 0, 2, 0, 1, 0, 1, 2, 0, 0, 1
Offset: 0

Views

Author

Ctibor O. Zizka, Jan 16 2018

Keywords

Comments

Sum_{i=0..n} a(i)/n = 3/4. For sequences of the type: a(0) = 1, in step n >= 0 add the term 1 at position floor(k*(n+a(n))), k rational number > 1 we have Sum_{i=0..n} a(i)/n = 1/k.

Examples

			Define a sequence b whose terms are initially b(0)=1 and, for n > 0, b(n)=0, i.e., b = {1,0,0,0,0,0,0,0,0,...}; then, for n = 0,1,2,..., increment b(floor(4*(n+b(n))/3)) by 1. For n >= 0, a(n) is the final value of b(n).
                                 Sequence b after b(k) is
n b(n) k=floor(4*(n+b(n))/3)         incremented by 1
= ==== =====================  ===============================
                              {1,0,0,0,0,0,0,0,0,0,0,0,0,...}
0   1  floor(4*(0+1)/3) =  1  {1,1,0,0,0,0,0,0,0,0,0,0,0,...}
1   1  floor(4*(1+1)/3) =  2  {1,1,1,0,0,0,0,0,0,0,0,0,0,...}
2   1  floor(4*(2+1)/3) =  4  {1,1,1,0,1,0,0,0,0,0,0,0,0,...}
3   0  floor(4*(3+0)/3) =  4  {1,1,1,0,2,0,0,0,0,0,0,0,0,...}
4   2  floor(4*(4+2)/3) =  8  {1,1,1,0,2,0,0,0,1,0,0,0,0,...}
5   0  floor(4*(5+0)/3) =  6  {1,1,1,0,2,0,1,0,1,0,0,0,0,...}
6   1  floor(4*(6+1)/3) =  9  {1,1,1,0,2,0,1,0,1,1,0,0,0,...}
7   0  floor(4*(7+0)/3) =  9  {1,1,1,0,2,0,1,0,1,2,0,0,0,...}
8   1  floor(4*(8+1)/3) = 12  {1,1,1,0,2,0,1,0,1,2,0,0,1,...}
		

Crossrefs

Cf. A136119.

Programs

  • Mathematica
    mx = 104; t = Join[{1}, 0 Range@mx]; k = 1; While[4 k < 3 (mx + 2), t[[ Floor[ 4(k + t[[k]])/3]]]++; k++]; Join[{1}, t] (* Robert G. Wilson v, Jan 18 2018 *)