12776743domain: NAppears in sequencesDenominator of Kirchhoff index of ladder graph L_n.at n=15A265031a(n) = numerator(r(n)) where r(n) = (((1/2)*(sqrt(3) + 1))^n - ((1/2)*(sqrt(3) - 1))^n * cos(Pi*n))/sqrt(3).at n=32A305491a(n) = U_{n}(n)/(n+1) where U_{n}(x) is a Chebyshev polynomial of the second kind.at n=7A318192