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 A265692 #12 Dec 23 2015 14:34:27 %S A265692 1,1,2,1,2,3,1,2,4,1,2,4,5,1,2,4,6,1,2,4,6,7,1,2,4,8,1,2,4,8,9,1,2,4, %T A265692 8,10,1,2,4,8,10,11,1,2,4,8,12,1,2,4,8,12,13,1,2,4,8,12,14,1,2,4,5,10, %U A265692 15,1,2,4,8,16,1,2,4,8,16,17,1,2,4,8,16,18,1,2,4,8,16,18,19,1,2,4,8,16,20 %N A265692 Irregular triangle read by rows: lexicographically last addition chain of minimal length for n. %C A265692 While addition chains are normally entered with terms in increasing order, the usual definition requires only that each term follows a pair of terms of which it is the sum. This sequence will eventually contain rows that are not monotonic; in particular, any non-Brauer number will have such a chain. What is the first number whose chain in this sequence is not monotonic? %C A265692 47 is the first number with a non-monotonic lexicographically last addition chain of minimal length: [1, 2, 4, 8, 16, 5, 21, 42, 47]. - _Alois P. Heinz_, Dec 22 2015 %C A265692 Needs a b-file. %H A265692 Wikipedia, <a href="https://en.wikipedia.org/wiki/Addition_chain">Addition chain</a> %e A265692 The table starts: %e A265692 1 %e A265692 1 2 %e A265692 1 2 3 %e A265692 1 2 4 %e A265692 1 2 4 5 %e A265692 1 2 4 6 %e A265692 1 2 4 6 7 %e A265692 1 2 4 8 %e A265692 ... %Y A265692 Cf. A265690 (row lengths), A265691 (smallest). %K A265692 nonn,tabf %O A265692 1,3 %A A265692 _Franklin T. Adams-Watters_, Dec 13 2015