

A056477


Number of primitive (aperiodic) palindromic structures using a maximum of three different symbols.


3



1, 0, 1, 1, 4, 3, 13, 12, 39, 36, 121, 116, 364, 351, 1088, 1080, 3280, 3237, 9841, 9800, 29510, 29403, 88573, 88440, 265716, 265356, 797121, 796796, 2391484, 2390352, 7174453
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OFFSET

1,5


COMMENTS

Permuting the symbols will not change the structure.


REFERENCES

M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.


LINKS

Table of n, a(n) for n=1..31.


FORMULA

a(n) = Sum mu(d)*b(n/d) where dn and b() = 1, 1, 2, 2, 5, 5, 14, 14, 41, 41, 122, 122, ... (A007051 repeated).


CROSSREFS

Cf. A056459.
Sequence in context: A169706 A120340 A082018 * A105200 A088933 A019136
Adjacent sequences: A056474 A056475 A056476 * A056478 A056479 A056480


KEYWORD

nonn


AUTHOR

Marks R. Nester (nesterm(AT)dpi.qld.gov.au)


STATUS

approved



