1703520domain: NAppears in sequencesE.g.f. (1-x^2)/(1-2x-x^2).at n=7A052622Location of records in A099564.at n=25A099565Numbers m such that A034448(A188999(m)) = k*m for some k, where A034448 and A188999 are respectively the unitary and the bi-unitary sigma function.at n=42A369204