A085348 Ratio-determined insertion sequence I(0.264) (see the link below).

1, 4, 19, 72, 341, 1292, 6119, 23184, 109801, 416020, 1970299, 7465176, 35355581, 133957148, 634430159, 2403763488, 11384387281, 43133785636, 204284540899, 774004377960, 3665737348901, 13888945017644, 65778987739319

Offset

0,2

Comments

This is one of the "twin" ratio-determined insertion sequences (RDIS) that are "children" in the next generation below the "parent" sequences I(0.25024) (A004253) and I(0.26816) (A001353) in the recurrence tree of RDIS sequences. The RDIS twin of this sequence is A085349. See the link for an explanation of RDIS twin. See A082630 or A082981 for other recent examples of RDIS sequences.

Links

Table of n, a(n) for n=0..22.

John W. Layman, Ratio-Determined Insertion Sequences and the Tree of their Recurrence Types, June 2003 [Broken link]

John W. Layman, Ratio-Determined Insertion Sequences and the Tree of their Recurrence Types, June 2003 [local copy, corrected]

John W. Layman, Sequences Generated by Age-Determined Insertion Trees, Jan 2006

John W. Layman, Sequences Generated by Age-Determined Insertion Trees, Jan 2006 [Local copy]

Formula

It appears that a(n)=18a(n-2)-a(n-4).

Apparently a(n)a(n+3) = -4 + a(n+1)a(n+2). - Ralf Stephan, May 29 2004

Crossrefs

Cf. A001353, A004253, A082630, A082981, A085349.

Sequence in context: A284224 A268214 A027208 * A027232 A256714 A110688

Adjacent sequences: A085345 A085346 A085347 * A085349 A085350 A085351

Keyword

nonn

Author

John W. Layman, Jun 24 2003

Status

approved