A303080 Number of n X 4 0..1 arrays with every element equal to 0, 2, 3, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
1, 20, 29, 90, 304, 1054, 4182, 17369, 75377, 335199, 1511973, 6877743, 31436925, 144097153, 661586920, 3040460522, 13981091806, 64311876578, 295889956660, 1361516449806, 6265388048955, 28833190731421, 132693419071842
Offset: 1
Keywords
Examples
Some solutions for n=5 ..0..0..0..1. .0..0..1..0. .0..1..1..0. .0..1..1..1. .0..0..0..1 ..0..0..0..1. .0..0..1..0. .1..1..1..0. .1..1..1..0. .0..0..0..1 ..0..1..0..1. .1..1..1..1. .0..1..1..0. .0..0..1..0. .0..0..0..0 ..0..0..0..1. .0..1..0..0. .0..1..1..0. .0..0..1..1. .1..1..1..1 ..0..0..0..0. .0..1..0..0. .1..1..1..0. .0..0..1..1. .1..1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A303084.
Formula
Empirical: a(n) = 8*a(n-1) -20*a(n-2) +40*a(n-3) -120*a(n-4) +154*a(n-5) -227*a(n-6) +511*a(n-7) +23*a(n-8) +913*a(n-9) -826*a(n-10) -2376*a(n-11) -4502*a(n-12) -920*a(n-13) +3818*a(n-14) +8855*a(n-15) -818*a(n-16) -403*a(n-17) +2092*a(n-18) +20390*a(n-19) +17737*a(n-20) +13494*a(n-21) +4257*a(n-22) +11150*a(n-23) +41175*a(n-24) +19200*a(n-25) -34770*a(n-26) -72210*a(n-27) -29661*a(n-28) +7521*a(n-29) +6424*a(n-30) -14914*a(n-31) -37578*a(n-32) -31048*a(n-33) +39954*a(n-34) +42548*a(n-35) -9756*a(n-36) -24760*a(n-37) -7244*a(n-38) +12262*a(n-39) +22816*a(n-40) +9539*a(n-41) -6968*a(n-42) -8366*a(n-43) +142*a(n-44) +5260*a(n-45) +1414*a(n-46) -1709*a(n-47) -1376*a(n-48) -1138*a(n-49) -624*a(n-50) +218*a(n-51) +300*a(n-52) +84*a(n-53) +36*a(n-54) +16*a(n-55) -16*a(n-56) for n>57.
Comments