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.

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A359214 a(n) is the least k >= 0 such that A359194^k(A358668(n)) = n (where A359194^k denotes the k-th iterate of A359194).

Original entry on oeis.org

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 2, 0, 4, 3, 0, 5, 0, 0, 1, 74, 0, 3, 7, 0, 1, 0, 0, 1, 5, 0, 0, 6, 0, 0, 2, 0, 77, 1, 0, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 8, 0, 0, 4, 0, 9, 1, 0, 0, 75, 0, 7, 6, 0, 8, 0, 0, 1, 0, 0, 76, 0, 0, 1, 5418, 0, 1, 0, 0, 2, 0, 0
Offset: 0

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Author

Rémy Sigrist, Dec 22 2022

Keywords

Examples

			The orbit of 0 under repeated application of A359194 is:
    0, 1, 0, ...
So a(0) = 0, a(1) = 1.
The orbit of 2 under repeated application of A359194 is:
    2, 1, 0, 1, 0, ...
So a(2) = 0.
The orbit of 3 under repeated application of A359194 is:
    3, 6, 13, 24, 55, 90, 241, 300, 123, 142, 85, 0, 1, 0, ...
So a(3) = 0, a(6) = 1, a(13) = 2, a(24) = 3, a(55) = 4, etc.
		

Crossrefs

Cf. A343858 (smallest numbers inside cyclic trajectories of the generalized Collatz function bx+c).

Programs

  • Mathematica
    nn = 83; c[] = -1; c[0] = 0; f[n] := FromDigits[BitXor[1, IntegerDigits[3*n, 2]], 2]; Do[(MapIndexed[If[c[#1] == -1, Set[c[#1], First[#2] - 1]] &, #]; -1 + Length[#]) &@ NestWhileList[f, n, c[#] == -1 && # > 1 &], {n, 0, nn}]; Array[c, nn] (* Michael De Vlieger, Dec 23 2022 *)
  • PARI
    See Links section.

Formula

a(n) = 0 iff A358668(n) = n.
a(3*n+2) = 0. - Thomas Scheuerle, Dec 22 2022
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