A000308 a(n) = a(n-1)*a(n-2)*a(n-3) with a(1)=1, a(2)=2 and a(3)=3.

1, 2, 3, 6, 36, 648, 139968, 3265173504, 296148833645101056, 135345882205792807436868315512832, 130876399105969522361889021452224949874232743897657526714368

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Examples

			a(6)=36*6*3=648.
		

Links

• John Cerkan, Table of n, a(n) for n = 1..15

Crossrefs

Cf. A000304, A000336, A063401.

Programs

Maple

A000308 := proc(n) option remember; if n <=3 then n else A000308(n-1)*A000308(n-2)*A000308(n-3); fi; end;

Formula

a(n) = 2^A001590(n-1)*3^A000073(n-1). - Henry Bottomley, Jul 16 2001