OFFSET
1,4
COMMENTS
The first negative term is a(120) = -3.
LINKS
FORMULA
MATHEMATICA
Block[{g}, g[n_] := If[n == 1, 0, PrimePi@FactorInteger[n][[1, 1]]]; Function[s, MapIndexed[Lookup[s, g[First@ #2] + 1][[#1]] - Boole[First@ #2 == 1] - DivisorSigma[1, First@ #2] &, #] &@ Map[Position[Lookup[s, g@ #], #][[1, 1]] &, Range@ 120]]@ PositionIndex@ Array[g, 10^4]] (* Michael De Vlieger, Oct 18 2021 *)
CROSSREFS
KEYWORD
sign,look
AUTHOR
Antti Karttunen, Jul 28 2021
STATUS
approved