

A200661


Number of 0..1 arrays x(0..n1) of n elements with each no smaller than the sum of its three previous neighbors modulo 2.


1



2, 3, 5, 8, 12, 17, 25, 36, 51, 72, 102, 144, 202, 284, 399, 560, 785, 1101, 1544, 2164, 3033, 4251, 5958, 8349, 11700, 16396, 22976, 32196, 45116, 63221, 88590, 124139, 173953, 243756, 341568, 478629, 670689, 939816, 1316935, 1845380, 2585874
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OFFSET

1,1


COMMENTS

Column 1 of A200668.


LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210


FORMULA

Empirical: a(n)=a(n1)+a(n2)a(n5)a(n6)+a(n7).
Empirical g.f.: x*(1 + x^2)*(2 + x  2*x^2  x^3 + x^4) / ((1  x)*(1  x^2  x^3  x^4 + x^6)).  Colin Barker, May 21 2018


EXAMPLE

Some solutions for n=6:
..0....0....0....0....0....1....0....0....0....1....1....1....0....0....1....0
..0....0....0....0....0....1....1....1....1....1....1....1....0....1....1....0
..0....1....0....0....1....0....1....1....1....0....0....0....0....1....1....1
..1....1....1....0....1....1....0....0....0....0....1....1....0....1....1....1
..1....0....1....0....1....1....0....1....1....1....0....1....0....1....1....0
..0....1....1....1....1....1....1....0....1....1....1....0....0....1....1....0


CROSSREFS

Cf. A200668.
Sequence in context: A347448 A024789 A318028 * A175539 A260795 A111388
Adjacent sequences: A200658 A200659 A200660 * A200662 A200663 A200664


KEYWORD

nonn


AUTHOR

R. H. Hardin, Nov 20 2011


STATUS

approved



