141214768242domain: NAppears in sequencesNumber of vertices in Sierpiński triangle of order n.at n=23A067771a(0) = 2, a(n) = 3*a(n-1) - 3.at n=24A115098a(n) = 6 * A015518(n).at n=23A120471a(n) = 3*A132357(n).at n=22A135264