cp's OEIS Frontend

A006447 Consider a 2-D cellular automaton generated by the Schrandt-Ulam rule of A170896, but confined to a semi-infinite strip of width n, starting with one ON cell at the top left corner; a(n) is the period of the resulting structure.

%I A006447 M0608 #27 Oct 04 2017 00:53:26
%S A006447 1,2,3,5,5,8,13,13,13,26,13,91,13,106,106,75,93,62,80,132,337,416,62,
%T A006447 62,62,271,34,155,525,548,1084,115,62,558,62,1500,2922,124,2958,3374,
%U A006447 2323,4183,8073,7925,744,2298,434,6700,310,23796,12732,26405
%N A006447 Consider a 2-D cellular automaton generated by the Schrandt-Ulam rule of A170896, but confined to a semi-infinite strip of width n, starting with one ON cell at the top left corner; a(n) is the period of the resulting structure.
%C A006447 Schrandt and Ulam remark that there seems to be no simple relation between n and a(n).
%C A006447 The original report included two further terms, but they were omitted from the published version, so are presumably unreliable.
%D A006447 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006447 J. T. Butler, <a href="/A006447/a006447.pdf">Letter to N. J. A. Sloane, Jun. 1975</a>.
%H A006447 R. G. Schrandt and S. M. Ulam, <a href="http://library.lanl.gov/cgi-bin/getfile?00359037.pdf">On recursively defined geometric objects and patterns of growth</a>, Los Alamos Scientific Laboratory, Report LA-3762, Aug 16 1967; published in A. W. Burks, editor, Essays on Cellular Automata. Univ. Ill. Press, 1970, pp. 238ff. [Link supplied by Laurinda J. Alcorn, Jan 09 2010]
%H A006447 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%K A006447 nonn
%O A006447 1,2
%A A006447 _N. J. A. Sloane_
%E A006447 Entry revised by _N. J. A. Sloane_, Jan 09 2010
%E A006447 More terms from _Sean A. Irvine_, Apr 13 2017