A056460 Number of primitive (aperiodic) palindromes using a maximum of four different symbols.

4, 0, 12, 12, 60, 48, 252, 240, 1008, 960, 4092, 4020, 16380, 16128, 65460, 65280, 262140, 261072, 1048572, 1047540, 4194036, 4190208, 16777212, 16772880, 67108800, 67092480, 268434432, 268419060, 1073741820, 1073675280, 4294967292, 4294901760, 17179865076, 17179607040, 68719476420

Offset: 1

Author

Marks R. Nester

Keywords

• nonn

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]

Crossrefs

Column 4 of A284823.

Cf. A056450.

Programs

PARI

a(n) = sumdiv(n, d, moebius(d)*(3*2^(n/d)-(-2)^(n/d))/2);
for(n=1, 40, print1(a(n), ", ")); \\ Petros Hadjicostas, Apr 24 2020

Formula

a(n) = Sum_{d|n} mu(d)*A056450(n/d).

Extensions

More terms from Petros Hadjicostas, Apr 24 2020