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A056486
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Number of periodic palindromes using a maximum of four different symbols.
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2
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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; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.
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FORMULA
| a(n)=4^((n+1)/2) for n odd, a(n)=4^(n/2)*5/2 for n even.
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EXAMPLE
| For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome.
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CROSSREFS
| Cf. A029744, A038754, A056450.
Sequence in context: A163389 A172126 A025621 * A061682 A038240 A001549
Adjacent sequences: A056483 A056484 A056485 * A056487 A056488 A056489
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KEYWORD
| nonn
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AUTHOR
| Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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