A087823 a(1) = a(2) = 1; for n > 2, a(n) = a(a(a(n-2))) + a(n-a(n-2)).

1, 1, 2, 3, 3, 3, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 11, 11, 11, 11, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 19, 19, 19, 20, 20, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22

Offset

1,3

Comments

A triply recursive version of A005229.

Links

Table of n, a(n) for n=1..77.

Mathematica

a[1] = a[2] = 1;
a[n_Integer?Positive] := a[n] =a[a[a[n-2]]] +a[n - a[n-2]];
Table[a[n], {n, 1, 200}]

Prog

(PARI) a=vector(100); a[1]=a[2]=1; for(n=3, #a, a[n] = a[a[a[n-2]]]+a[n-a[n-2]]); a \\ Altug Alkan, Oct 01 2017

Crossrefs

Cf. A005229, A005374.

Sequence in context: A308950 A193832 A293137 * A230418 A037037 A156262

Adjacent sequences: A087820 A087821 A087822 * A087824 A087825 A087826

Keyword

nonn,easy

Author

Roger L. Bagula, Oct 06 2003

Status

approved