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A281057 Number of 2 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 1, 6, 34, 104, 251, 535, 1076, 2090, 3956, 7353, 13474, 24417, 43846, 78142, 138374, 243687, 427098, 745403, 1296072, 2246018, 3880504, 6686165, 11491746, 19706373, 33722458, 57596214, 98195818, 167136611, 284039674, 482013727, 816869276 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

FORMULA

Empirical: a(n) = 5*a(n-1) - 7*a(n-2) - 2*a(n-3) + 10*a(n-4) - 2*a(n-5) - 5*a(n-6) + a(n-7) + a(n-8) for n>14.

Empirical g.f.: x^2*(1 + x + 11*x^2 - 22*x^3 - 29*x^4 + 18*x^5 + 43*x^6 + 14*x^7 - 31*x^8 - 13*x^9 + 8*x^10 + 2*x^11 - x^12) / ((1 - x)^2*(1 - x - x^2)^3). - Colin Barker, Feb 15 2019

EXAMPLE

Some solutions for n=4:

..0..0..0..1. .0..1..1..1. .0..1..1..0. .0..0..1..1. .0..1..0..0

..0..1..1..0. .0..0..1..0. .0..0..0..0. .1..1..0..1. .0..0..1..0

CROSSREFS

Row 2 of A281056.

Sequence in context: A319199 A305164 A067389 * A341290 A061616 A222308

Adjacent sequences: A281054 A281055 A281056 * A281058 A281059 A281060

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 13 2017

STATUS

approved

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Last modified December 1 08:58 EST 2022. Contains 358467 sequences. (Running on oeis4.)