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.

A246355 Rectangular array: T(n,k) is the position in the infinite Fibonacci word s = A003849 at which the block s(2)..s(n+1) occurs for the k-th time.

Original entry on oeis.org

2, 5, 2, 7, 5, 2, 10, 7, 7, 2, 13, 10, 10, 7, 2, 15, 13, 15, 10, 7, 2, 18, 15, 20, 15, 10, 10, 2, 20, 18, 23, 20, 15, 15, 10, 2, 23, 20, 28, 23, 20, 23, 15, 10, 2, 26, 23, 31, 28, 23, 31, 23, 15, 10, 2, 28, 26, 36, 31, 28, 36, 31, 23, 15, 10, 2, 31, 28, 41
Offset: 1

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Author

Clark Kimberling, Aug 24 2014

Keywords

Comments

Assuming that every row of T is infinite, each row contains the next row as a proper subsequence. Row 1 of A246354 and row 1 of A246355 partition the positive integers.

Examples

			The upper Wythoff sequence, A001950 gives the positions of 1 in A003849, which begins thus:  0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1.  For n = 1, the block s(2)..s(2) is simply 1, which occurs at positions 2,5,7,10,13,... as in row 1 of T.  For n = 5, the block s(2)..s(6) is 1,0,0,1,0 which occurs at positions 2,7,10,15,20,23, ...
The first 6 rows follow:
2 .. 5 .. 7 ... 10 .. 13 .. 15 .. 18 ...
2 .. 5 .. 7 ... 10 .. 13 .. 15 .. 18 ...
2 .. 7 .. 10 .. 15 .. 20 .. 23 .. 28 ...
2 .. 7 .. 10 .. 15 .. 20 .. 23 .. 28 ...
2 .. 7 .. 10 .. 15 .. 20 .. 23 .. 28 ...
2 .. 10 . 15 .. 23 .. 31 .. 36 .. 44 ...
		

Crossrefs

Programs

  • Mathematica
    z = 1000; s = Flatten[Nest[{#, #[[1]]} &, {0, 1}, 12]]; Flatten[Position[s, 1]]; b[m_, n_] := b[m, n] = Take[s, {m, n}]; z1 = 500; z2 = 12; t[k_] := t[k] = Take[Select[Range[1, z1], b[#, # + k] == b[2, 2 + k] &], z2]; Column[Table[t[k], {k, 0, z2}]](* A246355, array *)
    w[n_, k_] := t[n][[k + 1]]; Table[w[n - k, k], {n, 0, z2 - 1}, {k, n, 0, -1}] // Flatten (* A246355, sequence *)

Formula

First 2 rows: A001950 (upper Wythoff numbers);
next 3 rows: A035336 (Wythoff BA numbers);
next 5 rows: A134861 (Wythoff BAA numbers);
next 8 rows: (Wythoff BAAA numbers).
(The patterns continue; in particular the number of identical consecutive rows is always a Fibonacci number, as in A000045.)