login
A300642
Number of nX4 0..1 arrays with every element equal to 2, 3, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
1
0, 4, 10, 64, 316, 1789, 9738, 54293, 300456, 1669005, 9263141, 51430163, 285537725, 1585321263, 8801860535, 48868792430, 271324801628, 1506424664770, 8363834463324, 46436926280661, 257822913340328, 1431461142742217
OFFSET
1,2
COMMENTS
Column 4 of A300646.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +14*a(n-2) -17*a(n-3) -61*a(n-4) -49*a(n-5) -105*a(n-6) +151*a(n-7) +775*a(n-8) -58*a(n-9) -91*a(n-10) +1887*a(n-11) +512*a(n-12) +3274*a(n-13) +4088*a(n-14) -20637*a(n-15) -27360*a(n-16) -8376*a(n-17) -17162*a(n-18) +51171*a(n-19) +48004*a(n-20) +30560*a(n-21) +10871*a(n-22) -11625*a(n-23) -52251*a(n-24) -27283*a(n-25) -19433*a(n-26) -23710*a(n-27) +5592*a(n-28) +7218*a(n-29) -6323*a(n-30) +15212*a(n-31) +2942*a(n-32) -88*a(n-33) +4031*a(n-34) -1521*a(n-35) +534*a(n-36) -205*a(n-37) -151*a(n-38) +48*a(n-39) -135*a(n-40) +10*a(n-41) -47*a(n-42) +44*a(n-43) -13*a(n-44) -8*a(n-45) +12*a(n-46) -3*a(n-47) -2*a(n-48) +a(n-49)
EXAMPLE
Some solutions for n=5
..0..0..1..1. .0..0..1..1. .0..0..1..1. .0..0..0..0. .0..0..1..1
..0..0..1..1. .0..1..1..1. .0..0..1..0. .0..1..1..0. .0..0..1..0
..0..0..0..0. .0..0..0..0. .0..0..0..0. .0..1..1..0. .0..1..0..0
..1..1..0..0. .0..1..1..0. .0..1..0..0. .0..1..1..0. .1..0..0..1
..1..0..0..0. .1..1..0..0. .1..1..0..0. .0..0..0..0. .1..1..1..1
CROSSREFS
Cf. A300646.
Sequence in context: A323870 A298162 A203226 * A146304 A189893 A355375
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 10 2018
STATUS
approved