A084082 Length of lists created by n substitutions k -> range(-floor(abs(k)/2), abs(k)+1) starting with {0}.

1, 2, 5, 15, 49, 169, 604, 2212, 8244, 31128, 118716, 456337, 1765251, 6863852, 26803107, 105040906, 412905499, 1627313914, 6427849054, 25439373397

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Example

{0}, {0,1}, {0,1,0,1,2}, {0,1,0,1,2,0,1,0,1,2,-1,0,1,2,3}.

Mathematica

{Length/@Flatten/@NestList[ # /. k:(_Integer|_Rational):>Range[ -Floor[Abs[k]/2], Floor[Abs[k]+3/2]]&, {0}, 11]}

Crossrefs

Sequence in context: A148365 A001892 A176025 * A190270 A364588 A341342

Adjacent sequences: A084079 A084080 A084081 * A084083 A084084 A084085

Keyword

nonn,more

Author

Wouter Meeussen, May 11 2003

Extensions

Name simplified and a(13)-a(19) from Sean A. Irvine, Mar 10 2026

Status

approved