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 A357702 #15 Jul 03 2025 15:05:04 %S A357702 0,2,6,10,12,16,22,18,22,28,34,20,24,30,36,38,26,30,36,42,44,50,34,38, %T A357702 44,50,52,58,66,28,32,38,44,46,52,60,54,34,38,44,50,52,58,66,60,66,42, %U A357702 46,52,58,60,66,74,68,74,82,50,54,60,66,68,74,82,76,82,90 %N A357702 Path length (total depths of vertices) of the rooted binary tree with Colijn-Plazzotta tree number n. %C A357702 In a rooted binary tree each vertex has 0 or 2 children. %C A357702 All terms are even since each pair of 2 child vertices are at the same depth. %H A357702 Kevin Ryde, <a href="/A357702/a357702.gp.txt">PARI/GP Code</a> %F A357702 a(n) = a(x) + a(y) + A064002(n) - 1, for n>=2, where x = A002024(n-1) and y = A002260(n-1). %e A357702 For n=3, tree number 3 and the depth of each of its vertices is %e A357702 0 root %e A357702 / \ %e A357702 1 1 total depths %e A357702 / \ a(3) = 0 + 1+1 + 2+2 = 6 %e A357702 2 2 %o A357702 (PARI) \\ See links. %Y A357702 Cf. A357701 (vertex depths), A064002 (number of vertices). %Y A357702 Cf. A002024, A002260. %Y A357702 Cf. A196047 (in Matula-Goebel). %K A357702 nonn,easy %O A357702 1,2 %A A357702 _Kevin Ryde_, Oct 11 2022