A214352 - OEIS

A214352

T(n,k)=Number of nXnXn triangular 0..k arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors

2, 3, 6, 4, 17, 26, 5, 36, 169, 160, 6, 65, 660, 2853, 1386, 7, 106, 1951, 23554, 80573, 16814, 8, 161, 4822, 127813, 1602092, 3778867, 284724, 9, 232, 10507, 529006, 17790765, 205613460, 293207907, 6715224, 10, 321, 20840, 1807653, 135538054

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Table starts

....2.....3.......4........5.........6.........7..........8...........9

....6....17......36.......65.......106.......161........232.........321

...26...169.....660.....1951......4822.....10507......20840.......38421

..160..2853...23554...127813....529006...1807653....5349708....14150061

.1386.80573.1602092.17790765.135538054.790197579.3766437036.15329961031

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..99

FORMULA

Empirical: rows n=1..5 are polynomials of degree n(n+1)/2 in k

EXAMPLE

Some solutions for n=3 k=3

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

...0.1....3.0....1.1....0.2....2.1....1.2....3.1....0.2....2.0....3.3....3.2

..2.0.3..3.1.0..0.3.0..0.3.2..3.0.2..1.2.0..3.0.2..3.0.2..2.3.0..1.3.1..3.2.3

CROSSREFS

Column 1 is 2*A183278

Row 2 is A084990(n+1)

Sequence in context: A231263 A231451 A126063 * A248090 A229774 A137524

Adjacent sequences: A214349 A214350 A214351 * A214353 A214354 A214355

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Jul 13 2012

STATUS

approved