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A213795 Number of n X n 0..3 symmetric arrays with every row summing to floor(n*3/2). 0

%I #8 Apr 08 2020 01:56:54

%S 1,1,4,29,880,87932,34725760,46259653191,250599609089536,

%T 4664255347861848000,359514810915617810737152,

%U 96221422835240936091862618254,107926925135028470351157750883132800,423270762332675097186733226425581010359872

%N Number of n X n 0..3 symmetric arrays with every row summing to floor(n*3/2).

%e Some solutions for n=4

%e ..0..1..2..3....0..1..2..3....3..1..0..2....2..1..1..2....1..3..0..2

%e ..1..0..2..3....1..2..1..2....1..1..2..2....1..2..1..2....3..1..1..1

%e ..2..2..2..0....2..1..2..1....0..2..2..2....1..1..2..2....0..1..2..3

%e ..3..3..0..0....3..2..1..0....2..2..2..0....2..2..2..0....2..1..3..0

%Y Column 3 of A213800.

%K nonn

%O 0,3

%A _R. H. Hardin_, Jun 20 2012

%E a(0)=1 prepended and terms a(9) and beyond from _Andrew Howroyd_, Apr 07 2020

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Last modified July 17 04:19 EDT 2024. Contains 374360 sequences. (Running on oeis4.)