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A223640 Number of n X 4 0..1 arrays with rows, columns, diagonals and antidiagonals unimodal. 1
11, 121, 726, 2962, 9808, 28450, 74599, 179991, 404599, 855417, 1714062, 3275798, 6002946, 10596004, 18086161, 29953249, 48273537, 75902131, 116695104, 175776840, 259858436, 377613366, 540116971, 761356699, 1058820379, 1454170173 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A223644.

LINKS

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

FORMULA

Empirical: a(n) = (1/112)*n^8 - (19/210)*n^7 + (107/90)*n^6 - (197/40)*n^5 + (2219/144)*n^4 + (5093/120)*n^3 - (868411/2520)*n^2 + (417721/420)*n - 1091 for n>4.

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

G.f.: x*(11 + 22*x + 33*x^2 - 140*x^3 + 508*x^4 - 314*x^5 - 17*x^6 + 432*x^7 - 233*x^8 + 28*x^9 + 56*x^10 - 28*x^11 + 2*x^12) / (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>13.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A223644.

Sequence in context: A223392 A262468 A221964 * A223633 A223616 A223665

Adjacent sequences:  A223637 A223638 A223639 * A223641 A223642 A223643

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 24 2013

STATUS

approved

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Last modified October 25 06:19 EDT 2021. Contains 348239 sequences. (Running on oeis4.)