The On-Line Encyclopedia of Integer Sequences (OEIS)

A056463 revision #9

A056463

Number of primitive (aperiodic) palindromes using exactly two different symbols.

0, 0, 2, 2, 6, 4, 14, 12, 28, 24, 62, 54, 126, 112, 246, 240, 510, 476, 1022, 990, 2030, 1984, 4094, 4020, 8184, 8064, 16352, 16254, 32766, 32484, 65534, 65280, 131006, 130560, 262122, 261576, 524286, 523264, 1048446, 1047540, 2097150, 2094988, 4194302, 4192254

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

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

Andrew Howroyd, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = Sum_{d|n} mu(d)*A056453(n/d).

G.f.: Sum_{k>=1} mu(k)*2*x^(3*k)/((1 - 2*x^(2*k))*(1 - x^k)). - Andrew Howroyd, Sep 29 2019

PROG

(PARI) seq(n)={Vec(sum(k=1, n\3, moebius(k)*2*x^(3*k)/((1 - 2*x^(2*k))*(1 - x^k)) + O(x*x^n)), -n)} \\ Andrew Howroyd, Sep 29 2019

CROSSREFS

Column 2 of A327873.

Cf. A056453, A056458.

Sequence in context: A321451 A285943 A100495 * A309694 A325263 A365380

Adjacent sequences: A056460 A056461 A056462 * A056464 A056465 A056466