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A056486 Number of periodic palindromes using a maximum of four different symbols. +0
3
4, 10, 16, 40, 64, 160, 256, 640, 1024, 2560, 4096, 10240, 16384, 40960, 65536, 163840, 262144, 655360, 1048576, 2621440, 4194304, 10485760, 16777216, 41943040, 67108864, 167772160, 268435456, 671088640 (list; graph; listen)
OFFSET

1,1

REFERENCES

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

FORMULA

a(n)=4^((n+1)/2) for n odd, a(n)=4^(n/2)*5/2 for n even.

EXAMPLE

For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome.

CROSSREFS

Cf. A029744, A038754, A056450.

Adjacent sequences: A056483 A056484 A056485 this_sequence A056487 A056488 A056489

Sequence in context: A069982 A009883 A025621 this_sequence A061682 A038240 A001549

KEYWORD

nonn

AUTHOR

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

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Last modified October 11 13:47 EDT 2008. Contains 144830 sequences.


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