A211900 Number of triangular nXnXn arrays colored with integers 0 upwards introduced in row major order, with no element equal to any neighbor, and containing the value n(n+1)/2-3.

0, 1, 14, 274, 2315, 11866, 44821, 137859, 365604, 866530, 1880131, 3798191, 7233304, 13108109, 22769020, 38128546, 61840611, 97513599, 149966164, 225531160, 332413361, 481106956, 684879119

Offset

1,3

Comments

Column 2 of A211904

Links

Table of n, a(n) for n=1..23.

Formula

Empirical: a(n) = (1/128)*n^8 + (1/32)*n^7 - (41/192)*n^6 - (3/8)*n^5 + (329/128)*n^4 - (139/96)*n^3 - (467/96)*n^2 + (127/24)*n for n>1

Example

Some solutions for n=4
.....0........0........0........0........0........0........0........0
....1.2......1.2......1.2......1.2......1.2......1.2......1.2......1.2
...3.4.5....3.4.5....3.4.5....3.4.5....3.0.4....3.4.5....3.4.0....3.0.1
..4.6.0.7..6.7.6.3..6.7.0.7..4.0.6.7..5.6.7.0..6.7.1.8..5.6.2.7..4.5.6.7

Crossrefs

Sequence in context: A051690 A048668 A001820 * A215544 A205353 A279113

Adjacent sequences: A211897 A211898 A211899 * A211901 A211902 A211903

Keyword

nonn

Author

R. H. Hardin, Apr 25 2012

Status

approved