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%I #6 Aug 07 2021 21:34:24
%S 1,2,11,52,272,1414,7751,43208,246663,1430440,8414639,50065628,
%T 300830571,1822758766,11124755380,68328711696,422030545334,
%U 2619630794574,16332922290299,102240108466928,642312451209982,4048514835624478,25594403741131679,162250237951706584
%N a(n) = Sum_{d|n} mu(n/d) * binomial(3*d,d) / (2*d+1).
%C Moebius transform of A001764.
%t Table[Sum[MoebiusMu[n/d] Binomial[3 d, d]/(2 d + 1), {d, Divisors[n]}], {n, 24}]
%o (PARI) a(n) = sumdiv(n, d, moebius(n/d)*binomial(3*d, d)/(2*d+1)); \\ _Michel Marcus_, Aug 07 2021
%Y Cf. A001764, A002996, A008683.
%K nonn
%O 1,2
%A _Ilya Gutkovskiy_, Aug 07 2021
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