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A200661 Number of 0..1 arrays x(0..n-1) 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 (list; graph; refs; listen; history; text; internal format)
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(n-1)+a(n-2)-a(n-5)-a(n-6)+a(n-7).

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

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Last modified November 30 22:59 EST 2021. Contains 349426 sequences. (Running on oeis4.)