A226992 - OEIS

A226992

T(n,k)=Number of nXk 0..4 arrays of sums of 2X2 subblocks of some (n+1)X(k+1) binary array with rows and columns of the latter in lexicographically nondecreasing order

5, 10, 10, 15, 42, 15, 21, 120, 120, 21, 28, 313, 608, 313, 28, 36, 729, 2820, 2820, 729, 36, 45, 1556, 11325, 24158, 11325, 1556, 45, 55, 3099, 40431, 180712, 180712, 40431, 3099, 55, 66, 5818, 130479, 1187869, 2601925, 1187869, 130479, 5818, 66, 78, 10384

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OFFSET

1,1

COMMENTS

Table starts

..5....10......15........21..........28............36...............45

.10....42.....120.......313.........729..........1556.............3099

.15...120.....608......2820.......11325.........40431...........130479

.21...313....2820.....24158......180712.......1187869..........6897735

.28...729...11325....180712.....2601925......33118416........369163839

.36..1556...40431...1187869....33118416.....833294380......18415822936

.45..3099..130479...6897735...369163839...18415822936.....816606210291

.55..5818..385529..35818171..3630637294..357313893357...31841532264308

.66.10384.1054857.168412446.31856129416.6135150314839.1095361466285336

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..143

FORMULA

Empirical for column k:

k=1: a(n) = (1/2)*n^2 + (5/2)*n + 3 for n>1

k=2: [polynomial of degree 7] for n>4

k=3: [polynomial of degree 15] for n>7

k=4: [polynomial of degree 31] for n>15

EXAMPLE

Some solutions for n=4 k=4

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

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

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

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

CROSSREFS

Sequence in context: A038671 A101866 A331070 * A201033 A242894 A256641

Adjacent sequences: A226989 A226990 A226991 * A226993 A226994 A226995

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Jun 25 2013

STATUS

approved