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.

A103747 Trajectory of 2 under repeated application of the map n -> A102370(n).

Original entry on oeis.org

2, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 126, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 254, 258, 262, 266, 270, 274, 278, 282, 286, 290, 294, 298, 302, 306, 310, 314, 382, 386, 390, 394, 398, 402, 406, 410, 414, 418, 422
Offset: 1

Views

Author

Benoit Cloitre and David Applegate, Mar 25 2005

Keywords

Comments

Although it initially appears that a(n)-8n is the 16-periodic sequence {-2,-6,-10,-14,-18,-22,-26,-30,-34,-38,-42,-46,-50,-54,6,2}, this pattern eventually breaks down. However, the first divergence occurs beyond the first 400 million terms.
(a(n)) agrees with the 16-periodic sequence up to a(2^67-1) = 2^70 - 70, but then diverges with a(2^67) = 2^71 - 2. - Charlie Neder, Feb 07 2019

Crossrefs

Trajectories of other numbers: A103192 (1), A103621 (7), A158953 (12), A159887 (29).

Programs

  • Haskell
    a103747 n = a103747_list !! (n-1)
    a103747_list = iterate (fromInteger . a102370) 2
    -- Reinhard Zumkeller, Jul 21 2012

Extensions

Edited by Peter Munn, Jan 13 2024