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A variant of the recurrence for A001190.
2

%I #6 Mar 30 2012 16:47:49

%S 0,1,1,0,1,1,2,3,6,9,18,30,60,105,210,381,765,1425,2868,5454,11004,

%T 21210,42930,83673,169851,333843,679602,1345476,2745636,5467275,

%U 11182365,22379895,45866418,92180781,189275955,381831396,785328636

%N A variant of the recurrence for A001190.

%p A038751 := proc(n) option remember; local s,k; if n<=1 then RETURN(n); else s := 0; if n mod 2 = 0 then s := A038751(n/2) * (A038751(n/2) + 1)/2; for k from 1 to n/2 - 1 do s := s + A038751(k) * A038751(n - k); od; RETURN(s); else for k from 1 to (n - 1)/2 - 1 do s := s + A038751(k) * A038751(n - k); od; RETURN(s); fi; fi; end;

%Y Cf. A001190, A038750.

%K nonn

%O 0,7

%A _N. J. A. Sloane_, May 03 2000