The On-Line Encyclopedia of Integer Sequences (OEIS)

The OEIS is supported by the many generous donors to the OEIS Foundation.

Revision History for A026097

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A026097

a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, |s(i) - s(i-1)| = 1 for i = 1,2,3; |s(i) - s(i-1)| <= 1 for i >= 4. Also a(n) = sum of numbers in row n+1 of the array T defined in A026082 and a(n) = 24*3^(n-4) for n >= 4.
(history; published version)

#44 by Harvey P. Dale at Sat May 14 13:32:22 EDT 2022

STATUS

editing

approved

#43 by Harvey P. Dale at Sat May 14 13:32:19 EDT 2022

MATHEMATICA

Join[{1, 2, 4}, NestList[3#&, 8, 30]] (* Harvey P. Dale, May 14 2022 *)

STATUS

approved

editing

#42 by N. J. A. Sloane at Wed Mar 03 21:50:12 EST 2021

STATUS

proposed

approved

#41 by Michael De Vlieger at Wed Mar 03 21:37:44 EST 2021

STATUS

editing

proposed

#40 by Michael De Vlieger at Wed Mar 03 21:37:42 EST 2021

LINKS

M. Archibald, A. Blecher, and A. Knopfmacher, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL23/Blecher/arch14.html">Fixed Points in Compositions and Words</a>, J. Int. Seq., Vol. 23 (2020), Article 20.11.1.

STATUS

approved

editing

#39 by Peter Luschny at Mon Oct 19 16:43:25 EDT 2020

STATUS

reviewed

approved

#38 by Peter Luschny at Mon Oct 19 11:07:00 EDT 2020

STATUS

proposed

reviewed

#37 by Peter Luschny at Mon Oct 19 11:06:55 EDT 2020

STATUS

editing

proposed

#36 by Peter Luschny at Mon Oct 19 11:06:41 EDT 2020

FORMULA

a(n) = floor( (4*n-2)/(n+1) )*a(n-1). Without the floor function the recursion gives the Catalan numbers (A000108). - Hauke Woerpel, Oct 16 2020

STATUS

proposed

editing

#35 by Andrew Howroyd at Fri Oct 16 17:49:16 EDT 2020

STATUS

editing

proposed

Discussion

Sat Oct 17

04:32

Hauke Woerpel: Sounds good to me