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]
FORMULA
a(n) = Sum_{d|n} mu(d)*A001117(n/d).
PROG
(PARI) f(n) = 3^n - 3*2^n + 3;
a(n) = sumdiv(n, d, moebius(d)*f(n/d)); \\ Michel Marcus, Mar 25 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(11) and following corrected by Georg Fischer, Mar 24 2022
STATUS
approved