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]

6, 8, 8, 9, 9, 15, 20, 25, 29, 32, 37, 43, 46, 48, 50, 51, 51, 51, 52, 52, 52, 55, 56, 56, 56, 57, 57, 57, 59, 61, 62, 62, 62, 63, 63, 63, 66, 67, 67, 67, 68, 68, 68, 71, 73, 75, 76, 76, 76, 77, 77, 77, 80, 81, 81, 81, 82, 82, 82, 84, 86, 87, 87, 87, 88, 88, 88, 93, 94, 94

Offset

0,1

Links

A. Karttunen, Table of n, a(n) for n = 0..100

S. Wolfram, A New Kind of Science, Wolfram Media Inc., (2002), p. 102, p. 103 and pages 104, 896-898.

Formula

a(n) = A072643(A154471(n)) - A072643(A154472(n)).

Example

The iteration starts from the initial term e[e[e][e]][e][e], which contains 6 e's, thus a(0)=6.

Crossrefs

a(n) = A154475(n)+1.

Sequence in context: A281112 A229020 A113697 * A316858 A316859 A185200

Adjacent sequences: A154473 A154474 A154475 * A154477 A154478 A154479

Keyword

nonn

Author

Antti Karttunen, Jan 11 2009

Status

approved