A081831 a(1)=a(2)=1, a(n) = a(a(n - a(n-1))) + a(n - a(n-2)).

1, 1, 2, 3, 3, 3, 5, 4, 5, 5, 5, 8, 6, 6, 8, 8, 8, 8, 8, 12, 9, 8, 10, 11, 11, 12, 12, 12, 12, 12, 12, 20, 12, 10, 15, 17, 16, 13, 18, 16, 15, 20, 17, 19, 20, 20, 20, 20, 20, 20, 20, 32, 17, 16, 21, 24, 25, 18, 18, 32, 25, 20, 21, 27, 25, 26, 28, 28, 23, 32, 28, 24, 32, 32, 25, 31

Offset

1,3

Links

Muniru A Asiru, Table of n, a(n) for n = 1..10000

Formula

Conjecture: a(n)/n -> C = 0.2....

Maple

a:= proc(n) option remember: if n<3 then 1 else procname(procname(n-procname(n-1)))+ procname(n-procname(n-2)) fi end: seq(a(n), n=1..80); # Muniru A Asiru, Jun 04 2018

Mathematica

a[1]=a[2]=1; a[n_]:=a[n]=a[a[n-a[n-1]]]+a[n-a[n-2]]; Table[a[n], {n, 80}] (* Harvey P. Dale, Aug 04 2019 *)

Prog

(GAP) a:=[1, 1];; for n in [3..80] do a[n]:=a[a[n-a[n-1]]]+a[n-a[n-2]]; od; a; # Muniru A Asiru, Jun 04 2018

Crossrefs

Cf. A005185.

Sequence in context: A213617 A205778 A328972 * A349837 A111912 A096288

Adjacent sequences: A081828 A081829 A081830 * A081832 A081833 A081834

Keyword

nonn

Author

Benoit Cloitre, Apr 10 2003

Status

approved