A094943 / A sequence generated from a semi-magic square

[Alec Mihailovs]

"Gottfried Helms" <Annette.Warlich at t-online.de> wrote,
>>
>> If the matrix-method given in the example below can be extended to higher
>> order, then this would be a much more handy rule to compute the 
>> coefficients
>> than to employ a symbolic algebra program and evaluate the nominator for
>> higher orders ...

It is easier to use recurrences,

{a(n+3)=3*a(n+2)+15*a(n+1)+18*a(n), a(0) = 1, a(1) = 13, a(2) = 72}

for A094943 and

{a(n+4)=4*a(n+3)+44*a(n+2)+144*a(n+1)+160*a(n), a(0) = 1, a(1) = 26, a(2) = 
256, a(3) = 2472}

for the 4x4 matrix generated sequence.

Alec Mihailovs,
http://math.tntech.edu/alec/