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A270607 Number of 2X2X2 triangular 0..n arrays with some element plus some adjacent element totalling n+1 or n-1 exactly once. 1
6, 0, 36, 36, 96, 120, 204, 252, 360, 432, 564, 660, 816, 936, 1116, 1260, 1464, 1632, 1860, 2052, 2304, 2520, 2796, 3036, 3336, 3600, 3924, 4212, 4560, 4872, 5244, 5580, 5976, 6336, 6756, 7140, 7584, 7992, 8460, 8892, 9384, 9840, 10356, 10836, 11376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A270606.

LINKS

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

FORMULA

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

Empirical for n mod 2 = 0: a(n) = 6*n^2 - 18*n + 12 for n>1

Empirical for n mod 2 = 1: a(n) = 6*n^2 - 18*n + 36 for n>1

EXAMPLE

Some solutions for n=4

...4....2....4....4....3....2....1....0....1....3....1....4....0....1....0....2

..0.3..4.3..1.0..2.3..2.4..3.4..4.3..4.3..0.3..4.0..3.0..3.2..2.1..4.0..1.2..0.1

CROSSREFS

Cf. A270606.

Sequence in context: A047762 A186977 A167316 * A051768 A262888 A262894

Adjacent sequences:  A270604 A270605 A270606 * A270608 A270609 A270610

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 20 2016

STATUS

approved

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Last modified July 8 07:34 EDT 2020. Contains 335513 sequences. (Running on oeis4.)