login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A056279 Number of primitive (aperiodic) word structures of length n which contain exactly three different symbols. 2
0, 0, 1, 6, 25, 89, 301, 960, 3024, 9305, 28501, 86430, 261625, 788669, 2375075, 7140720, 21457825, 64435896, 193448101, 580597110, 1742343323, 5228050949, 15686335501, 47063113320, 141197991000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same 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..25.

FORMULA

sum mu(d)*A000392(n/d) where d|n and n>0.

CROSSREFS

Column 3 of A137651.

Cf. A056268.

Sequence in context: A099625 A209243 A143628 * A055337 A309946 A001871

Adjacent sequences:  A056276 A056277 A056278 * A056280 A056281 A056282

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 August 10 01:38 EDT 2020. Contains 336361 sequences. (Running on oeis4.)