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A226870 T(n,k)=Number of nXk (-1,0,1) arrays of determinants of 2X2 subblocks of some (n+1)X(k+1) binary array with rows and columns of the latter in lexicographically nondecreasing order 6
2, 4, 4, 7, 13, 7, 11, 37, 37, 11, 16, 91, 187, 91, 16, 22, 199, 792, 792, 199, 22, 29, 397, 2866, 6195, 2866, 397, 29, 37, 736, 9136, 41222, 41222, 9136, 736, 37, 46, 1285, 26267, 235528, 523701, 235528, 26267, 1285, 46, 56, 2134, 69311, 1179663, 5692900 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

..2....4......7.......11.........16...........22............29............37

..4...13.....37.......91........199..........397...........736..........1285

..7...37....187......792.......2866.........9136.........26267.........69311

.11...91....792.....6195......41222.......235528.......1179663.......5279390

.16..199...2866....41222.....523701......5692900......53537470.....442630782

.22..397...9136...235528....5692900....119835087....2182420206...34737998303

.29..736..26267..1179663...53537470...2182420206...77611438870.2412616653873

.37.1285..69311..5279390..442630782..34737998303.2412616653873

.46.2134.170084.21450391.3265819433.489248332852

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..112

FORMULA

Empirical: column k is a polynomial in n of degree 3*2^(k-1)-1 for k in 1..5 and n>0,0,1,5,13

EXAMPLE

Some solutions for n=4 k=4

..0..0.-1..0....0..0..0..0....0..0.-1..1....0..0.-1..0....0.-1..1..0

..0.-1.-1..0....0..0..0..0....0.-1..0..0....0.-1.-1..0....0..0..0..0

.-1..0..0..0...-1..1..0..0....0..0..0.-1...-1.-1..1..0....0..0..0..0

..0..0..1..0....0..0..0..0....0..0..0..1....0..0..0..0...-1..1.-1..1

CROSSREFS

Column 1 is A000124

Sequence in context: A297085 A224158 A224409 * A227751 A268995 A205744

Adjacent sequences:  A226867 A226868 A226869 * A226871 A226872 A226873

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Jun 20 2013

STATUS

approved

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Last modified May 26 13:05 EDT 2019. Contains 323586 sequences. (Running on oeis4.)