A128485 a(1)=a(2)=a(3)=1; for n > 3, a(n) = lcm(a(n-1) + a(n-2), a(n-3)).

1, 1, 1, 2, 3, 5, 8, 39, 235, 1096, 51909, 2491235, 348410728, 6071656665789, 15126791566796828495, 1317584644380565684408069688, 7999921680639175567165604204659004361387

Offset

1,4

Links

Table of n, a(n) for n=1..17.

Maple

a[1]:=1: a[2]:=1: a[3]:=1: for n from 4 to 18 do a[n]:=lcm(a[n-1]+a[n-2], a[n-3]) od: seq(a[n], n=1..18); # Emeric Deutsch, May 22 2007

Crossrefs

Sequence in context: A041008 A041569 A268480 * A042471 A041871 A061249

Adjacent sequences: A128482 A128483 A128484 * A128486 A128487 A128488

Keyword

nonn

Author

Leroy Quet, May 07 2007

Extensions

More terms from Emeric Deutsch, May 22 2007

Status

approved