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 A154476 #5 Jul 22 2025 06:18:18 %S A154476 6,8,8,9,9,15,20,25,29,32,37,43,46,48,50,51,51,51,52,52,52,55,56,56, %T A154476 56,57,57,57,59,61,62,62,62,63,63,63,66,67,67,67,68,68,68,71,73,75,76, %U A154476 76,76,77,77,77,80,81,81,81,82,82,82,84,86,87,87,87,88,88,88,93,94,94 %N A154476 Number of e's in each iteration of Wolfram's e[x_][y_] -> x[x[y]] symbolic rewriting system, starting from the initial state e[e[e][e]][e][e]. %H A154476 A. Karttunen, <a href="/A154476/b154476.txt">Table of n, a(n) for n = 0..100</a> %H A154476 S. Wolfram, <a href="http://www.wolframscience.com/nksonline/page-102">A New Kind of Science, Wolfram Media Inc., (2002), p. 102</a>, <a href="http://www.wolframscience.com/nksonline/page-103">p. 103</a> and pages 104, 896-898. %F A154476 a(n) = A072643(A154471(n)) - A072643(A154472(n)). %e A154476 The iteration starts from the initial term e[e[e][e]][e][e], which contains 6 e's, thus a(0)=6. %Y A154476 a(n) = A154475(n)+1. %K A154476 nonn %O A154476 0,1 %A A154476 _Antti Karttunen_, Jan 11 2009