

A252872


Number of n X 4 nonnegative integer arrays with upper left 0 and lower right n+44 and value increasing by 0 or 1 with every step right or down.


2



3, 26, 153, 615, 1953, 5281, 12686, 27805, 56624, 108549, 197804, 345216, 580452, 944778, 1494415, 2304572, 3474241, 5131844, 7441827, 10612301, 14903835, 20639511, 28216356, 38118271, 50930582, 67356343, 88234526, 114560238
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OFFSET

1,1


LINKS

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


FORMULA

Empirical: a(n) = (1/8064)*n^8 + (1/288)*n^7 + (103/2880)*n^6 + (17/90)*n^5 + (655/1152)*n^4 + (331/288)*n^3  (677/1120)*n^2  (41/120)*n + 2.
Empirical: G.f.: x*(3x+27*x^278*x^3+120*x^4110*x^5+59*x^617*x^7+2*x^8) / (x1)^9.  R. J. Mathar, Nov 23 2015


EXAMPLE

Some solutions for n=3
..0..0..1..1....0..0..0..1....0..0..1..1....0..1..1..2....0..1..1..1
..0..0..1..2....0..0..1..2....0..1..2..2....0..1..2..2....0..1..1..2
..1..1..2..3....0..1..2..3....1..2..3..3....0..1..2..3....1..1..2..3


CROSSREFS

Column 4 of A252876.
Sequence in context: A034495 A034493 A265467 * A121626 A038697 A226351
Adjacent sequences: A252869 A252870 A252871 * A252873 A252874 A252875


KEYWORD

nonn


AUTHOR

R. H. Hardin, Dec 24 2014


STATUS

approved



