The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A331986 Number of snake-like polyominoes with the maximum possible number of unit squares in an n X n square. 6
 1, 4, 8, 84, 56, 136, 52, 216, 16, 1504, 2352, 1152, 1344, 123216, 82432, 11008, 308992 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The maximum possible number of unit squares is given by A331968(n). Equivalently, a(n) is the number of maximum length paths without chords in the n X n grid graph. A path without chords is an induced subgraph that is a path. For n > 1, a(n) is a multiple of 4 since a solution can have at most one symmetry considering rotations and reflections. - Andrew Howroyd, Feb 04 2020 LINKS Table of n, a(n) for n=1..17. Eric Weisstein's World of Mathematics, Grid Graph EXAMPLE For n = 4 the number of snake-like polyominoes with 11 cells is 84. CROSSREFS Main diagonal of A360916. Cf. A331968, A059525 (connected induced subgraphs), A099155. Cf. A332920 (non-isomorphic snakes), A332921 (symmetric snakes). Sequence in context: A090254 A222287 A120281 * A057974 A071277 A336795 Adjacent sequences: A331983 A331984 A331985 * A331987 A331988 A331989 KEYWORD nonn,walk,hard,more AUTHOR Alain Goupil, Feb 03 2020 EXTENSIONS a(15) from Andrew Howroyd, Feb 04 2020 a(16)-a(17) from Yi Yang, Oct 03 2022 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 10 17:16 EDT 2023. Contains 363206 sequences. (Running on oeis4.)