A203256 Number of nX2 0..7 arrays with every nonzero element less than or equal to some NW, E or S neighbor

1, 64, 2598, 62098, 1224456, 24301646, 508333573, 10796311201, 227388709221, 4758047352741, 99544750655412, 2085847467997684, 43730820112478471, 916653540455467303, 19210279580301799126, 402581567408971305348

Offset

1,2

Comments

Column 2 of A203262

Links

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

Formula

Empirical: a(n) = 64*a(n-1) -1848*a(n-2) +33600*a(n-3) -431592*a(n-4) +4086840*a(n-5) -29206462*a(n-6) +160678294*a(n-7) -693264590*a(n-8) +2392550992*a(n-9) -6777430404*a(n-10) +16251895568*a(n-11) -33600669981*a(n-12) +59027125766*a(n-13) -84488023983*a(n-14) +94715868410*a(n-15) -83342440797*a(n-16) +62202372085*a(n-17) -42529439142*a(n-18) +24388393885*a(n-19) -9901259764*a(n-20) +2690832600*a(n-21) -486202500*a(n-22)

Example

Some solutions for n=4
..4..0....6..0....3..4....5..4....0..0....2..7....6..4....6..0....5..7....0..1
..4..3....6..4....1..4....5..4....3..0....1..7....6..6....6..3....6..7....0..7
..4..0....6..0....4..4....5..3....3..0....7..7....0..0....6..4....7..7....7..7
..4..4....6..6....0..4....5..5....3..3....1..7....0..0....6..6....0..7....7..7

Crossrefs

Sequence in context: A239432 A004388 A269291 * A265632 A144843 A284228

Adjacent sequences: A203253 A203254 A203255 * A203257 A203258 A203259

Keyword

nonn

Author

R. H. Hardin Dec 30 2011

Status

approved