OFFSET
28,3
FORMULA
G.f.: Sum_{k>=1} mu(k)* x^(28*k) / Product_{j=1..7} (1 - x^(j*k)).
MATHEMATICA
nmax = 80; CoefficientList[Series[Sum[MoebiusMu[k] x^(28 k)/Product[1 - x^(j k), {j, 1, 7}], {k, 1, nmax}], {x, 0, nmax}], x] // Drop[#, 28] &
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 23 2021
STATUS
approved