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A056500 Number of primitive (period n) periodic palindromes using exactly four different symbols. 2
0, 0, 0, 0, 0, 12, 24, 132, 240, 900, 1560, 4968, 8400, 24588, 40824, 113520, 186480, 502248, 818520, 2157360, 3497976, 9085452, 14676024, 37723260, 60780720, 155082900, 249401640, 632947728, 1016542800, 2569816476, 4123173624, 10393520640 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,6
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
FORMULA
a(n) = Sum_{d|n} mu(d)*A056490(n/d).
EXAMPLE
For example, aaabbb is not a (finite) palindrome but it is a periodic palindrome.
CROSSREFS
Column 4 of A327878.
Sequence in context: A051385 A290304 A289335 * A056490 A130163 A002167
KEYWORD
nonn
AUTHOR
EXTENSIONS
Terms corrected by Andrew Howroyd, Sep 28 2019
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)