A268787 Number of nX6 binary arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two exactly once.
20, 338, 4207, 46195, 477128, 4725018, 45515227, 429442918, 3988796543, 36591758790, 332327545513, 2993282062865, 26773510121640, 238060527618025, 2105957538309226, 18547209960131466, 162707970808249851
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..0..0..0..1..0. .0..0..1..0..0..0. .0..1..0..0..0..0. .0..1..0..1..0..1 ..1..0..0..1..0..0. .0..0..0..1..0..0. .0..0..1..0..1..0. .0..0..1..0..0..0 ..0..1..0..0..0..1. .0..0..0..0..1..1. .0..0..0..1..0..0. .0..0..0..0..1..0 ..0..0..1..0..0..0. .0..0..0..0..0..0. .0..0..0..0..1..0. .1..0..0..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A268789.
Formula
Empirical: a(n) = 2*a(n-1) +83*a(n-2) +210*a(n-3) -1918*a(n-4) -13444*a(n-5) -27431*a(n-6) +22868*a(n-7) +172414*a(n-8) +91292*a(n-9) -572846*a(n-10) -576908*a(n-11) +1569339*a(n-12) +1662464*a(n-13) -4129647*a(n-14) -2739590*a(n-15) +10005684*a(n-16) +128072*a(n-17) -18820309*a(n-18) +14239344*a(n-19) +18275195*a(n-20) -39512592*a(n-21) +16595129*a(n-22) +32600294*a(n-23) -63035320*a(n-24) +55225574*a(n-25) -27556538*a(n-26) +5959238*a(n-27) +1367780*a(n-28) -935764*a(n-29) -205936*a(n-30) +253428*a(n-31) -6946*a(n-32) -44268*a(n-33) +5192*a(n-34) +6896*a(n-35) -1085*a(n-36) -848*a(n-37) +74*a(n-38) +94*a(n-39) +3*a(n-40) -6*a(n-41) -a(n-42)
Comments