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A283779
Number of nX3 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.
1
0, 5, 60, 745, 7298, 62303, 496884, 3767599, 27544383, 195862137, 1362432578, 9309699590, 62681109851, 416796696040, 2742095941841, 17874537516228, 115580492689760, 742070620542530, 4734351638158905, 30034414798026318
OFFSET
1,2
COMMENTS
Column 3 of A283784.
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) -69*a(n-2) +107*a(n-3) -309*a(n-4) +1218*a(n-5) -502*a(n-6) +4740*a(n-7) -5256*a(n-8) +3491*a(n-9) -27390*a(n-10) +288*a(n-11) -31284*a(n-12) +59157*a(n-13) +45831*a(n-14) +125150*a(n-15) +14523*a(n-16) -89694*a(n-17) -228321*a(n-18) -273708*a(n-19) -34062*a(n-20) +168784*a(n-21) +436860*a(n-22) +297456*a(n-23) +20424*a(n-24) -252768*a(n-25) -337248*a(n-26) -116736*a(n-27) +40320*a(n-28) +115200*a(n-29) +64000*a(n-30)
EXAMPLE
Some solutions for n=4
..0..1..1. .1..1..1. .1..0..1. .0..1..1. .1..1..1. .0..0..0. .0..1..1
..1..1..1. .0..1..1. .1..1..1. .1..0..1. .1..0..1. .1..0..0. .0..0..0
..1..0..1. .0..0..0. .0..1..0. .0..1..0. .1..1..0. .1..1..0. .1..1..1
..1..0..0. .0..1..1. .1..1..1. .0..1..1. .1..1..0. .1..1..1. .1..1..0
CROSSREFS
Cf. A283784.
Sequence in context: A099672 A320361 A138134 * A353875 A370445 A093885
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 16 2017
STATUS
approved