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A056464
Number of primitive (aperiodic) palindromes using exactly three different symbols.
4
0, 0, 0, 0, 6, 6, 36, 36, 150, 144, 540, 534, 1806, 1770, 5790, 5760, 18150, 17994, 55980, 55830, 170970, 170466, 519156, 518580, 1569744, 1567944, 4733670, 4732014, 14250606, 14244660, 42850116, 42844320, 128746410, 128728800
OFFSET
1,5
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)*A056454(n/d).
MAPLE
with(numtheory):with(combinat, stirling2):A056454:=n->3!*stirling2(floor((n+1)/2), 3); A056464:=n->add(mobius(d)*A056454(n/d), d=divisors(n)); # C. Ronaldo
CROSSREFS
Column 3 of A327873.
Sequence in context: A165827 A256136 A111437 * A056454 A056452 A183622
KEYWORD
nonn
STATUS
approved