2324522935domain: NAppears in sequencesa(n) = 1 + 2*3^(n-1) with a(0)=2.at n=20A0529192*3^n-(-1)^n.at n=19A081632Number of layers of dough separated by butter in successive foldings of croissant dough.at n=20A100702a(n) = 6*9^n+1.at n=9A199564