A201723 - OEIS

A201723

Number of nX2 0..4 arrays with rows and columns lexicographically nondecreasing and no element equal to the number of horizontal and vertical neighbors equal to itself

10, 90, 631, 3567, 16493, 64018, 213013, 621757, 1626046, 3878550, 8560638, 17688966, 34541082, 64226182, 114429139, 196357695, 325924563, 525198174, 824157734, 1262790173, 1893568514, 2784353134, 4021759333, 5715036571

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 2 of A201729

LINKS

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

FORMULA

Empirical: a(n) = (27/560)*n^8 + (153/140)*n^7 - (1841/40)*n^6 + (29593/40)*n^5 - (474291/80)*n^4 + (1992631/120)*n^3 + (7057023/70)*n^2 - (200552137/210)*n + 2321607 for n>13

EXAMPLE

Some solutions for n=6

..0..2....0..0....2..4....0..0....0..0....0..3....0..0....2..3....0..2....0..0

..0..4....0..3....2..4....0..2....1..4....0..3....0..0....3..4....0..2....0..1

..2..4....2..0....3..2....1..3....2..2....0..3....0..4....4..0....0..3....0..2

..3..0....2..0....4..1....2..1....3..1....0..3....1..0....4..0....0..3....1..0

..3..0....3..4....4..4....3..2....3..3....0..3....4..0....4..0....2..0....2..0

..3..1....4..2....4..4....3..2....4..3....0..3....4..4....4..1....2..0....2..4

CROSSREFS

Sequence in context: A065690 A202919 A202576 * A228418 A306958 A306957

Adjacent sequences: A201720 A201721 A201722 * A201724 A201725 A201726

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 04 2011

STATUS

approved