A270607 Number of 2 X 2 X 2 triangular 0..n arrays with some element plus some adjacent element totaling n+1 or n-1 exactly once.

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

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