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A223682 Number of 4 X n 0..1 arrays with rows and antidiagonals unimodal. 1
16, 256, 2032, 9822, 35509, 105995, 275775, 646407, 1395174, 2815594, 5372794, 9777124, 17079747, 28794301, 47049089, 74774613, 115931628, 175785252, 261231028, 381179194, 547003777, 773063487, 1077301747, 1481933555 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A223680.

LINKS

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

FORMULA

Empirical: a(n) = (1/112)*n^8 + (79/1260)*n^7 + (121/120)*n^6 + (71/36)*n^5 + (475/48)*n^4 - (1757/180)*n^3 + (8893/840)*n^2 - (569/84)*n + 9.

Conjectures from Colin Barker, Aug 22 2018: (Start)

G.f.: x*(16 + 112*x + 304*x^2 - 594*x^3 + 775*x^4 - 442*x^5 + 216*x^6 - 36*x^7 + 9*x^8) / (1 - x)^9.

a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) for n>9.

(End)

EXAMPLE

Some solutions for n=3:

..1..1..0....0..0..1....1..0..0....0..0..0....0..1..1....1..1..0....0..1..0

..1..1..0....0..0..0....0..1..0....1..1..0....0..1..0....0..1..0....0..0..1

..0..1..1....0..0..0....1..0..0....0..1..1....0..0..0....1..1..0....1..1..1

..0..0..1....0..1..1....0..1..0....1..1..0....0..1..1....1..0..0....0..1..0

CROSSREFS

Cf. A223680.

Sequence in context: A188994 A208075 A223641 * A189066 A189191 A188876

Adjacent sequences:  A223679 A223680 A223681 * A223683 A223684 A223685

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 25 2013

STATUS

approved

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Last modified January 27 18:20 EST 2022. Contains 350611 sequences. (Running on oeis4.)