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%I #7 Feb 03 2021 20:09:46
%S 1,2,13,189,4842,190080,10520010,777018690,73646397720,8696221929360,
%T 1249994376199800,214673857998276600,43377963701592920400,
%U 10180798532673708139200,2745082427076790292091600,842339587833332705318202000,291745985923439508815578224000
%N Number of n X n matrices over {0,1,2} with all row and column sums equal to 1 or 2.
%D I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983,(Problem 3.4.15).
%H Andrew Howroyd, <a href="/A062156/b062156.txt">Table of n, a(n) for n = 0..100</a>
%e There are 13 2 X 2 matrices over {0,1,2} with all row and column sums equal to 1 or 2, cf. A062154.
%Y Main diagonal of A062154.
%Y Cf. A062155.
%K easy,nonn
%O 0,2
%A _Vladeta Jovovic_, Jun 06 2001
%E Terms a(15) and beyond from _Andrew Howroyd_, Feb 03 2021