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A278802 Number of nX3 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order. 1

%I

%S 10,63,322,1439,5767,20972,69834,214774,615120,1653047,4196501,

%T 10123619,23327383,51572441,109818385,225997932,450803519,873872396,

%U 1649976645,3040564120,5478446820,9666837555,16728604905,28427944695,47495149011

%N Number of nX3 0..2 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order.

%C Column 3 of A278807.

%H R. H. Hardin, <a href="/A278802/b278802.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = (1/20922789888000)*n^16 + (1/201180672000)*n^15 + (257/1046139494400)*n^14 + (1/130636800)*n^13 + (19241/114960384000)*n^12 + (3523/1306368000)*n^11 + (241517/7315660800)*n^10 + (284771/914457600)*n^9 + (336468511/146313216000)*n^8 + (35482669/2612736000)*n^7 + (376442771/5748019200)*n^6 + (46737917/179625600)*n^5 + (361669107043/435891456000)*n^4 + (250175041/127008000)*n^3 + (375648041/121080960)*n^2 + (13891/5040)*n + 1

%e Some solutions for n=4

%e ..1..1..0. .1..1..0. .1..0..0. .0..0..0. .1..1..0. .2..1..0. .1..0..0

%e ..2..0..2. .2..1..1. .1..2..0. .0..0..0. .1..1..0. .2..1..0. .1..1..1

%e ..2..2..0. .2..1..2. .1..2..1. .0..0..0. .1..1..1. .2..1..0. .1..1..1

%e ..2..2..0. .2..1..2. .2..2..2. .1..0..0. .2..1..0. .2..2..1. .2..2..0

%Y Cf. A278807.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 28 2016

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Last modified May 28 00:30 EDT 2022. Contains 354110 sequences. (Running on oeis4.)