A087774 a[1] = 1, a[2] = a[3] = 2; a[n] = 3*a[a[n-1]] - 3*a[n-a[n-1]]+a[n-3].

11, 2, 2, 1, 2, 5, 1, 2, 8, 1, 2, 11, 1, 2, 14, 1, 2, 17, 1, 2, 20, 1, 2, 23, 1, 2, 26, 1, 2, 29, 1, 2, 32, 1, 2, 35, 1, 2, 38, 1, 2, 41, 1, 2, 44, 1, 2, 47, 1, 2, 50, 1, 2, 53, 1, 2, 56, 1, 2, 59, 1, 2, 62, 1, 2, 65, 1, 2, 68, 1, 2, 71, 1, 2, 74, 1, 2, 77, 1, 2, 80, 1, 2, 83, 1, 2, 86, 1, 2, 89, 1

Offset

0,1

Comments

A recursive finite third derivative sequence. A tick-tock sequence of the form 1,2,a(n-3)+3

Links

Table of n, a(n) for n=0..90.

Mathematica

hg[n_Integer?Positive] := hg[n] =3*hg[hg[n-1]] -3*hg[n-hg[n-1]]+hg[n-3] hg[1]=1 hg[2]=2 hg[3]=2 digits=200 a=Table[hg[n], {n, 1, digits}]

Crossrefs

Cf. A004001, A087775.

Sequence in context: A010190 A323454 A261353 * A322562 A040118 A099268

Adjacent sequences: A087771 A087772 A087773 * A087775 A087776 A087777

Keyword

nonn

Author

Roger L. Bagula, Oct 04 2003

Status

approved