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A253070
The subsequence A253069(2^n-1).
2
1, 6, 22, 82, 302, 1106, 4066, 14902, 54678, 200578, 735770, 2699182, 9901550, 36323050, 133247570, 488805718, 1793137798, 6577952882, 24130592458, 88520767614, 324729961566, 1191240790586, 4369952806274, 16030753627238, 58807285300086, 215728897446594, 791380812129402, 2903104763095054
OFFSET
0,2
COMMENTS
A253069 is the Run Length Transform of this sequence.
LINKS
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, A Meta-Algorithm for Creating Fast Algorithms for Counting ON Cells in Odd-Rule Cellular Automata, arXiv:1503.01796, 2015; see also the Accompanying Maple Package.
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, Odd-Rule Cellular Automata on the Square Grid, arXiv:1503.04249, 2015.
N. J. A. Sloane, On the No. of ON Cells in Cellular Automata, Video of talk in Doron Zeilberger's Experimental Math Seminar at Rutgers University, Feb. 05 2015: Part 1, Part 2
N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168, 2015
FORMULA
G.f.: (1+2*x)*(1+x-x^2+x^3+2*x^5)/(1-3*x-3*x^2+x^3+6*x^4-10*x^5+8*x^6-8*x^7). - Doron Zeilberger, Feb 18 2015
MAPLE
OddCA2:=proc(f, M) local n, a, i, f2, g, p;
f2:=simplify(expand(f)) mod 2;
p:=1; g:=f2;
for n from 1 to M do p:=expand(p*g) mod 2; print(n, nops(p)); g:=expand(g^2) mod 2; od:
return;
end;
f:=1/x+1+x+x/y+y/x+x*y;
OddCA2(f, 10);
MATHEMATICA
LinearRecurrence[{3, 3, -1, -6, 10, -8, 8}, {1, 6, 22, 82, 302, 1106, 4066}, 28] (* Jean-François Alcover, Nov 27 2017 *)
PROG
(PARI) Vec(-(2*x+1)*(2*x^5+x^3-x^2+x+1)/(8*x^7-8*x^6+10*x^5-6*x^4-x^3+3*x^2+3*x-1) + O(x^30)) \\ Colin Barker, Jul 16 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jan 29 2015
EXTENSIONS
a(11) and a(12) (Maple on a 32 GB machine) from R. J. Mathar, Feb 04 2015
a(13) onwards from Doron Zeilberger, Feb 18 2015 (the terms previously listed were wrong). - N. J. A. Sloane, Feb 19 2015
STATUS
approved