A335751 - OEIS

%I #10 Jun 21 2020 06:01:47

%S 2,6,15,63,225,693,1289925,4455,34459425,808782975,5685805125,

%T 4106936925,18767808934875,72977109975,491292329653125,

%U 305714614450620375,1578522255175490625,33864491287501875,6076788748684677645496875,34996278233163121875,55478375013295336399171875

%N a(n) = denominator(Bernoulli(2*n)*(1/2 - n)! / sqrt(Pi)).

%F a(n) = denominator(-2*n*Zeta(1 - 2*n)*(1/2 - n)! / sqrt(Pi)) for n >= 1.

%e r(n) = 1/2, 1/6, 1/15, 2/63, 4/225, 8/693, 11056/1289925, 32/4455, ...

%p a := n -> bernoulli(2*n)*(1/2 - n)! / sqrt(Pi):

%p seq(denom(simplify(a(n))), n = 0..21);

%Y Cf. A335750 (numerator), A000367/A002445, A004193.

%K nonn,frac

%O 0,1

%A _Peter Luschny_, Jun 20 2020