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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 6
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 (list; table; graph; refs; listen; history; text; internal format)
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
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
KEYWORD
nonn,tabl
AUTHOR
R. H. Hardin Jun 25 2013
STATUS
approved

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Last modified June 25 10:55 EDT 2024. Contains 373701 sequences. (Running on oeis4.)