A048112 a(1) = 1, a(2) = 1, a(3) = 1, a(n) = a(n-3) * (a(n-2) + a(n-1)).

1, 1, 1, 2, 3, 5, 16, 63, 395, 7328, 486549, 195081415, 1433122040192, 697379012200764243, 136045964066902820948075525, 194970470582876525091946983913863955456

Offset

1,4

Links

Table of n, a(n) for n=1..16.

Mathematica

RecurrenceTable[{a[1]==a[2]==a[3]==1, a[n]==a[n-3] (a[n-2]+a[n-1])}, a, {n, 20}] (* Harvey P. Dale, Jan 14 2012 *)
nxt[{a_, b_, c_}]:={b, c, a(b+c)}; NestList[nxt, {1, 1, 1}, 20][[;; , 1]] (* Harvey P. Dale, Jul 14 2024 *)

Crossrefs

Cf. A048122.

Sequence in context: A192648 A219339 A360695 * A001042 A214697 A379775

Adjacent sequences: A048109 A048110 A048111 * A048113 A048114 A048115

Keyword

nonn,easy

Author

David Johnson-Davies

Extensions

More terms from Patrick De Geest, Jun 15 1999

Status

approved