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.
%I A323454 #29 Jan 09 2025 13:00:16 %S A323454 0,1,11,2,-1,10,9,3,9,-1,10,9,5,8,-1,4,7,8,8,-1,10,9,6,8,-1,5,8,7,9, %T A323454 -1,6,5,10,6,-1,9,9,7,9,-1,11,10,7,9,-1,6,9,8,10,-1,7,6,7,7,-1,6,7,8, %U A323454 8,-1,7,6,11,6,-1,10,10,7,10,-1,8,8,9,8,-1,8,11,8 %N A323454 Minimal number of steps to reach n from 1 using "Choix de Bruxelles", version 2 (cf. A323460), or -1 if n cannot be reached. %C A323454 This is equally the minimal number of steps to reach n from 1 using "Choix de Bruxelles", version 1 (cf. A323286), or -1 if n cannot be reached. %C A323454 n cannot be reached if its final digit is 0 or 5, but all other numbers can be reached (see comments in A323286). %H A323454 Rémy Sigrist, <a href="/A323454/b323454.txt">Table of n, a(n) for n = 1..10000</a> %H A323454 Eric Angelini, Lars Blomberg, Charlie Neder, Remy Sigrist, and N. J. A. Sloane, <a href="http://arxiv.org/abs/1902.01444">"Choix de Bruxelles": A New Operation on Positive Integers</a>, arXiv:1902.01444, Feb 2019; Fib. Quart. 57:3 (2019), 195-200. %H A323454 Eric Angelini, Lars Blomberg, Charlie Neder, Remy Sigrist, and N. J. A. Sloane,, <a href="/A307635/a307635.pdf">"Choix de Bruxelles": A New Operation on Positive Integers</a>, Local copy. %H A323454 Brady Haran and N. J. A. Sloane, <a href="https://www.youtube.com/watch?v=AeqK96UX3rA">The Brussels Choice</a>, Numberphile video (2020) %H A323454 N. J. A. Sloane, Coordination Sequences, Planing Numbers, and Other Recent Sequences (II), Experimental Mathematics Seminar, Rutgers University, Jan 31 2019, <a href="https://vimeo.com/314786942">Part I</a>, <a href="https://vimeo.com/314790822">Part 2</a>, <a href="https://oeis.org/A320487/a320487.pdf">Slides.</a> (Mentions this sequence) %e A323454 Examples of optimal ways to reach 1,2,3,...: %e A323454 1 %e A323454 1, 2 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 14, 12, 6, 3 %e A323454 1, 2, 4 %e A323454 5 cannot be reached, ends in 0 or 5 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 14, 12, 6 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 14, 7 %e A323454 1, 2, 4, 8, %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 18, 9. %e A323454 10 cannot be reached, ends in 0 or 5 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 24, 22, 11 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 14, 12 %e A323454 1, 2, 4, 8, 16, 13 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 14 %e A323454 15 cannot be reached, ends in 0 or 5 %e A323454 1, 2, 4, 8, 16 %e A323454 1, 2, 4, 8, 16, 32, 34, 17 %e A323454 1, 2, 4, 8, 16, 112, 56, 28, 18 %e A323454 1, 2, 4, 8, 16, 32, 34, 38, 19 %e A323454 20 cannot be reached, ends in 0 or 5 %e A323454 ... %Y A323454 Cf. A323286-A323289, A323453, A323484, A323460. %Y A323454 For variants of the Choix de Bruxelles operation, see A337321 and A337357. %K A323454 sign,base %O A323454 1,3 %A A323454 _N. J. A. Sloane_, Jan 15 2019 %E A323454 More terms from _Rémy Sigrist_, Jan 15 2019