A106742 a(n) = a(a(a(a(a(n - a(n-1)))))) + a(n - a(n-2)) with a(1) = a(2) = 1.

1, 1, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13

Offset

1,3

Comments

A sixth-order recursion based on A005185.

Different from A087839 - see comments in that entry.

Different from A106733.

Links

Paolo P. Lava, Table of n, a(n) for n = 1..10000

Formula

a(n) = a(a(a(a(a(n -a(n-1)))))) + a(n-a(n-2)) with a(1) = a(2) = 1.

Mathematica

a[n_]:= a[n]= If[n<3, 1, a[a[a[a[a[n - a[n-1]]]]]] + a[n - a[n-2]]];
Table[a[n], {n, 90}]

Prog

(Sage)
@CachedFunction
def a(n): return 1 if (n<3) else a(a(a(a(a(n -a(n-1)))))) + a(n-a(n-2));
[a(n) for n in (1..90)] # G. C. Greubel, Sep 11 2021

Crossrefs

Cf. A004001, A005185, A087836, A087839, A087842, A106733.

Sequence in context: A130247 A209869 A087839 * A106733 A087838 A057627

Adjacent sequences: A106739 A106740 A106741 * A106743 A106744 A106745

Keyword

nonn

Author

Roger L. Bagula, May 30 2005

Extensions

Edited by N. J. A. Sloane, Jun 15 2007

Status

approved