Question 913724
The rows ( a,b,c ) can be filled as follows:
1,1,3
1,3,1
3,1,1
------
1,2,2
2,1,2
2,2,1
------
These are NOT allowed:
0,1,4
1,0,4
0,4,1
1,4,0
4,0,1
4,1,0
----
5,0,0
0,5,0
0,0,5
----
Each of the ( allowed ) seating plans
can have {{{ 5*4*3*2*1 = 120 }}}
so, there can be
{{{ 6*120 = 720 }}} possible seatings
This is my best guess