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%I #4 Jan 15 2022 21:37:12
%S 1,3,9,18,80,196,554,1824,2292,7218,45522,288135,660113,3201130,
%T 10512530,17675063,191230544,207521990
%N Main diagonal of the triangular array A161136.
%F a(m) = A161136(m,m).
%Y Cf. A161135, A161136, A161137.
%K more,nonn
%O 1,2
%A _Max Alekseyev_, Jun 02 2009