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A206261 Number of (n+1) X 3 0..1 arrays with the number of rightwards and downwards edge increases in each 2 X 2 subblock equal to the number in all its horizontal and vertical neighbors. 1
24, 28, 44, 64, 93, 128, 174, 228, 295, 372, 464, 568, 689, 824, 978, 1148, 1339, 1548, 1780, 2032, 2309, 2608, 2934, 3284, 3663, 4068, 4504, 4968, 5465, 5992, 6554, 7148, 7779, 8444, 9148, 9888, 10669, 11488, 12350, 13252, 14199, 15188, 16224, 17304 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A206267.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-3) +3*a(n-4) -a(n-5) for n>6.

Conjectures from Colin Barker, Jun 14 2018: (Start)

G.f.: x*(24 - 44*x + 8*x^2 + 36*x^3 - 27*x^4 + 5*x^5) / ((1 - x)^4*(1 + x)).

a(n) = (72 + 26*n + 9*n^2 + n^3) / 6 for n>1 and even.

a(n) = (78 + 26*n + 9*n^2 + n^3) / 6 for n>1 and odd.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Cf. A206267.

Sequence in context: A268540 A030500 A107406 * A217441 A045668 A045659

Adjacent sequences:  A206258 A206259 A206260 * A206262 A206263 A206264

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 05 2012

STATUS

approved

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Last modified September 27 20:35 EDT 2020. Contains 337388 sequences. (Running on oeis4.)