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%I #6 Aug 05 2024 11:26:30
%S 1,1,4,7,17,36,88,196,481,1148,2838,7020,17708,44837,114971,296457
%N Graded dimension of the space of invariant bilinear forms on the free pre-Lie algebra on one generator.
%C The sequence starts at index 5 because the previous terms vanish.
%F It seems that a(n+1) = A000081(n) - A051573(n). - _Andrey Zabolotskiy_, Aug 05 2024
%Y This is related in some sense to A000081.
%Y Cf. A051573, A123256.
%K nonn,more
%O 5,3
%A _F. Chapoton_, Sep 14 2004