A284077 Number of 3Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.

0, 0, 15, 275, 3174, 31898, 300008, 2695374, 23315931, 196337438, 1619907608, 13142006271, 105144896153, 831492737200, 6510374422284, 50537297389064, 389357648148684, 2979896274369314, 22671924767160815, 171584668641301626

Offset

1,3

Comments

Row 3 of A284075.

Links

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

Formula

Empirical: a(n) = 15*a(n-1) -60*a(n-2) +125*a(n-3) -1137*a(n-4) +2028*a(n-5) +539*a(n-6) +39918*a(n-7) +71109*a(n-8) +182402*a(n-9) +118347*a(n-10) -296751*a(n-11) -1143516*a(n-12) -2568462*a(n-13) -2234631*a(n-14) +771008*a(n-15) +7215516*a(n-16) +14200866*a(n-17) +12041819*a(n-18) -2280720*a(n-19) -23475099*a(n-20) -35927647*a(n-21) -23058894*a(n-22) +10637571*a(n-23) +37847467*a(n-24) +34806129*a(n-25) +8813067*a(n-26) -14068429*a(n-27) -18555168*a(n-28) -9925527*a(n-29) -713731*a(n-30) +3039399*a(n-31) +2593371*a(n-32) +1126644*a(n-33) +233214*a(n-34) -32427*a(n-35) -39237*a(n-36) -11907*a(n-37) -705*a(n-38) +613*a(n-39) +174*a(n-40) +12*a(n-41) -8*a(n-42)

Example

Some solutions for n=4
..0..1..1..1. .1..0..0..0. .0..1..1..0. .1..0..1..1. .0..0..1..1
..1..1..0..1. .1..1..1..1. .1..1..1..1. .0..1..1..1. .1..1..1..1
..1..1..1..0. .1..1..1..0. .1..1..0..1. .1..1..1..0. .0..0..1..1

Crossrefs

Cf. A284075.

Sequence in context: A195615 A156091 A194728 * A339118 A034687 A159239

Adjacent sequences: A284074 A284075 A284076 * A284078 A284079 A284080

Keyword

nonn

Author

R. H. Hardin, Mar 19 2017

Status

approved