A204861 Number of (n+2)X4 0..1 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly two different ways, and new values 0..1 introduced in row major order

382, 1648, 7127, 31034, 136899, 603605, 2660367, 11721609, 51702644, 227902203, 1004799769, 4430100363, 19531105570, 86110306240, 379643708799, 1673789364704, 7379441106496, 32534731009926, 143440092995732

Offset

1,1

Comments

Column 2 of A204867

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +7*a(n-2) +21*a(n-3) +a(n-4) -74*a(n-5) -162*a(n-6) +138*a(n-7) -18*a(n-8) +1187*a(n-9) -2509*a(n-10) -1249*a(n-11) +375*a(n-12) -3916*a(n-13) +29438*a(n-14) -20835*a(n-15) +21040*a(n-16) -41934*a(n-17) -21760*a(n-18) +100360*a(n-19) -54423*a(n-20) +171105*a(n-21) -190049*a(n-22) -55439*a(n-23) -103559*a(n-24) +4935*a(n-25) +72883*a(n-26) -32323*a(n-27) +95561*a(n-28) -221835*a(n-29) +320810*a(n-30) -176564*a(n-31) +95261*a(n-32) +33740*a(n-33) -115048*a(n-34) +86489*a(n-35) -210476*a(n-36) +35609*a(n-37) -117190*a(n-38) +191186*a(n-39) +95961*a(n-40) -27689*a(n-41) +89312*a(n-42) -83490*a(n-43) +9205*a(n-44) +61964*a(n-45) -55123*a(n-46) +33185*a(n-47) -16169*a(n-48) -5814*a(n-49) +12737*a(n-50) -3837*a(n-51) -410*a(n-52) -140*a(n-53) -740*a(n-54) +184*a(n-55) +104*a(n-56) -24*a(n-57) for n>58

Example

Some solutions for n=3
..0..0..0..1....0..1..1..0....0..1..0..0....0..0..0..0....0..0..0..0
..0..1..0..1....1..1..0..0....1..0..0..0....0..1..0..0....1..1..1..0
..1..0..0..1....1..1..0..0....1..1..0..1....0..1..1..1....0..0..1..0
..1..1..0..1....0..1..1..1....1..1..0..1....0..1..0..0....0..1..1..0
..0..0..0..1....0..1..1..0....1..0..0..1....1..1..0..0....1..0..1..0

Crossrefs

Sequence in context: A201800 A172848 A214896 * A015861 A072385 A045122

Adjacent sequences: A204858 A204859 A204860 * A204862 A204863 A204864

Keyword

nonn

Author

R. H. Hardin Jan 20 2012

Status

approved