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 A218609 #21 Mar 08 2025 14:51:26 %S A218609 0,1,2,8,3,60,172,12,20,49,54,3016,10096,125744802,101035235,25, %T A218609 1358590114,40796719636668219,70,19049,1770,18,7,16261, %U A218609 82682568533587123,17,36,307,315899951699378231,3871315398,15215587727307698,59,9097520004151634187729920190004140 %N A218609 Distinct values of A218787 in the order of appearance. %C A218609 a(n) = A014486-index for the n-th tendril of the infinite beanstalk (A179016), which has not been encountered before, constructed with lesser numbers coming to the left, and larger to the right hand side of each branch. %H A218609 Antti Karttunen, <a href="/A218609/b218609.txt">Table of n, a(n) for n = 1..72</a> %H A218609 Antti Karttunen, <a href="/A014486/a014486_1.pdf">Illustration of how binary trees (the second rightmost column) are encoded by A014486</a> %F A218609 a(n) = A218787(A218611(n)). %o A218609 (Scheme) (define (A218609 n) (A218787 (A218611 n))) %Y A218609 These are the mirror-images of binary trees given in A218610, i.e. a(n) = A057163(A218610(n)). A218613 gives the sizes of these trees. Cf. A218611. %K A218609 nonn %O A218609 1,3 %A A218609 _Antti Karttunen_, Nov 11 2012