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A028576 a(n) = (1/(4*n)) * Sum_{d|n} mu(n/d) * binomial(2*d, d)^2. 1

%I #11 Oct 30 2018 03:34:57

%S 1,4,33,304,3175,35556,420665,5176000,65664000,853367900,11309870605,

%T 152342891952,2080240006923,28738242567524,401024083514775,

%U 5645275548076800,80084088088568947,1143862232096407392,16437995698573558421,237520818846111947600

%N a(n) = (1/(4*n)) * Sum_{d|n} mu(n/d) * binomial(2*d, d)^2.

%o (PARI) a(n) = sumdiv(n, d, moebius(n/d)*binomial(2*d, d)^2)/(4*n) \\ _Michel Marcus_, Jun 15 2013

%K nonn

%O 1,2

%A Lionel Levine (levine(AT)ultranet.com)

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)