A224131 Number of n X 6 0..1 arrays with rows nondecreasing and antidiagonals unimodal.

7, 49, 269, 1279, 5648, 24095, 101412, 425246, 1783229, 7484923, 31443217, 132153826, 555559627, 2335689630, 9819848422, 41284852413, 173569002429, 729710418743, 3067802281464, 12897441557475, 54222509714920

Offset

1,1

Comments

Column 6 of A224133.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 14*a(n-2) + 9*a(n-3) + 4*a(n-5) + 16*a(n-6).

Empirical g.f.: x*(7 + 24*x^2 + 19*x^3 + 20*x^4 + 16*x^5) / (1 - 7*x + 14*x^2 - 9*x^3 - 4*x^5 - 16*x^6). - Colin Barker, Aug 27 2018

Example

Some solutions for n=3:
..1..1..1..1..1..1....1..1..1..1..1..1....0..0..0..0..1..1....0..0..0..0..1..1
..0..1..1..1..1..1....0..1..1..1..1..1....0..0..0..1..1..1....0..0..0..0..1..1
..0..0..0..0..1..1....0..1..1..1..1..1....0..1..1..1..1..1....0..0..0..0..0..0

Crossrefs

Cf. A224133.

Sequence in context: A203059 A203383 A293887 * A218266 A213295 A189258

Adjacent sequences: A224128 A224129 A224130 * A224132 A224133 A224134

Keyword

nonn

Author

R. H. Hardin, Mar 31 2013

Status

approved