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%I #20 Jun 05 2021 06:03:22
%S 1,4,10,32,110,392,1428,5280,19734,74360,281996,1074944,4115020,
%T 15808912,60917800,235350720,911315430,3535767000,13742347740,
%U 53495534400,208537056420,813950932080,3180614712600,12441628655040
%N Central elements in 4-Pascal triangle A028275 (by row).
%C Equals A000984, [1, 2, 6, 20, 70, ...] convolved with [1, 2, 0, 0, 0, ...]. - _Gary W. Adamson_, Jun 05 2009
%F a(n) = 2*A051960(n-1).
%F a(n) = 2*A000108(n)*(3n-1). - _Ralf Stephan_, Aug 24 2003
%Y Cf. A000108, A028275, A051960.
%K nonn,easy
%O 0,2
%A _Mohammad K. Azarian_
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