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%I #14 Dec 01 2019 07:15:33
%S 0,0,1,1,10,54,204,243,1594,4210,18484,62174,275828,1131980,7434360,
%T 10522755,72469530,268486410,1442238420,4284331050,18146556060,
%U 62021100660,248289237960,798007353390,2832660378756,11922780597588
%N Sum of proper divisors of Catalan number A000108(n).
%H Amiram Eldar, <a href="/A152762/b152762.txt">Table of n, a(n) for n = 0..1667</a>
%F a(n) = A001065(A000108(n)).
%F a(n) = sigma(binomial(2n,n)/(n+1)) - binomial(2n,n)/(n+1), where sigma(m) is the sum of the divisors of m. - _Emeric Deutsch_, Dec 24 2008
%e a(4)=10 because the proper divisors of A000108(4)=14 are 1,2 and 7. - _Emeric Deutsch_, Dec 24 2008
%p with(numtheory): seq(sigma(binomial(2*n, n)/(n+1))-binomial(2*n, n)/(n+1), n = 0 .. 27); # _Emeric Deutsch_, Dec 24 2008
%t DivisorSigma[1,#]-#&/@CatalanNumber[Range[0,30]] (* _Harvey P. Dale_, Dec 05 2015 *)
%Y Cf. A000108, A000203, A001065, A152761, A152763.
%K easy,nonn
%O 0,5
%A _Omar E. Pol_, Dec 14 2008
%E Extended by _Emeric Deutsch_, Dec 24 2008
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