516891375domain: NAppears in sequencesDenominators of coefficients in expansion of x^-2*(1-exp(-2*x))^2.at n=17A104097Denominator of c(n) = 2^(2*n)*(2^(2*n) - 1)/(2*n)!, a coefficient used in the expansion of tan(x) as Sum_{n>=1} c(n)*|Bernoulli(2*n)|*x^(2*n-1).at n=9A225846