17572253481domain: NAppears in sequencesExpansion of (1-x)^2/(1 - 4*x + 3*x^2 - x^3).at n=21A0525441 followed by A141015.at n=33A142474INVERT transform of [1, 0, 1, 3, 9, 27, 81, ...].at n=22A204200