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A252872 Number of n X 4 nonnegative integer arrays with upper left 0 and lower right n+4-4 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 (list; graph; refs; listen; history; text; internal format)
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*(3-x+27*x^2-78*x^3+120*x^4-110*x^5+59*x^6-17*x^7+2*x^8) / (x-1)^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

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Last modified July 29 12:51 EDT 2021. Contains 346346 sequences. (Running on oeis4.)