24466266999domain: NAppears in sequencesa(n) = Catalan(n) - n.at n=21A246604A246604 (Catalan(n)-n) with initial terms 1,0,0,2 changed to 1,1,1,3.at n=21A289615A246604 (Catalan(n)-n) with initial terms 1,0,0,2,10 changed to 1,1,1,2,11.at n=21A289616