login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A056333 Number of primitive (aperiodic) reversible string structures with n beads using a maximum of four different colors. 3
1, 1, 3, 9, 30, 102, 378, 1440, 5607, 22155, 87978, 350775, 1400490, 5597487, 22379145, 89498880, 357952170, 1431737433, 5726775978, 22906819575, 91626580269, 366505186047, 1466017950378, 5864067254880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

A string and its reverse are considered to be equivalent. Permuting the colors will not change the structure.

REFERENCES

M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2]

LINKS

Table of n, a(n) for n=1..24.

FORMULA

Sum mu(d)*A056323(n/d) where d|n.

CROSSREFS

Cf. A056315.

Sequence in context: A048119 A304823 A317875 * A148948 A148949 A148950

Adjacent sequences:  A056330 A056331 A056332 * A056334 A056335 A056336

KEYWORD

nonn

AUTHOR

Marks R. Nester

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 11 22:31 EST 2019. Contains 329046 sequences. (Running on oeis4.)