A300461 Number of nX4 0..1 arrays with every element equal to 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
0, 4, 8, 28, 142, 540, 2585, 11343, 51501, 233028, 1052448, 4769842, 21579345, 97715668, 442378911, 2002838338, 9067930634, 41054700887, 185876096558, 841553822832, 3810142997823, 17250454214015, 78101569076062
Offset: 1
Keywords
Examples
Some solutions for n=5 ..0..0..1..1. .0..0..0..0. .0..0..0..0. .0..0..1..1. .0..0..0..1 ..0..0..1..1. .0..1..0..0. .0..1..1..0. .0..1..1..0. .0..0..1..1 ..0..1..0..0. .1..1..1..1. .1..1..0..0. .0..0..0..0. .0..1..1..1 ..1..0..0..1. .1..0..0..1. .1..0..0..1. .0..1..1..1. .0..0..0..0 ..1..1..1..1. .0..0..1..1. .1..1..1..1. .1..1..1..1. .0..0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A300465.
Formula
Empirical: a(n) = 4*a(n-1) +6*a(n-2) -5*a(n-3) -37*a(n-4) -59*a(n-5) -39*a(n-6) +80*a(n-7) -279*a(n-8) +328*a(n-9) +1083*a(n-10) -25*a(n-11) +6234*a(n-12) +6280*a(n-13) -5927*a(n-14) +13954*a(n-15) -677*a(n-16) -53183*a(n-17) +32616*a(n-18) -49693*a(n-19) -57573*a(n-20) +142653*a(n-21) -126299*a(n-22) +100762*a(n-23) +71676*a(n-24) -234851*a(n-25) +178322*a(n-26) -92379*a(n-27) -11243*a(n-28) +181969*a(n-29) -91225*a(n-30) +44201*a(n-31) -9047*a(n-32) -83657*a(n-33) +21643*a(n-34) +39079*a(n-35) -7039*a(n-36) -11806*a(n-37) +2726*a(n-38) +9392*a(n-39) -18923*a(n-40) +27265*a(n-41) -28247*a(n-42) +17148*a(n-43) -7200*a(n-44) +2338*a(n-45) +517*a(n-46) -867*a(n-47) -170*a(n-48) +576*a(n-49) -297*a(n-50) +60*a(n-51) -4*a(n-52) for n>54
Comments