105722domain: NAppears in sequencesa(n) = Sum_{k=0..2*n-2} T(n, k)*T(n, k+2), T given by A027960.at n=6A027986Revert transform of (-1 + 3x^2)/(-1 - x + 4x^2 + x^3).at n=16A049132Least number x such that x^n has n digits equal to k. Case k = 1.at n=34A285448