A123181 Numbers such that (-1)Sigma(m)*UnitarySigma(m)= k*UnitaryPhi(m)*m for some integer k.

1, 6, 312, 495, 990, 20520, 23664, 64416, 13063050

Offset

1,2

Comments

R. J. Mathar did an exhaustive search up to 74000000. Kohmoto found one more term, 2^8*3*11*43*257*509 with k=3, but between 7.4*10^7 and this term, many terms may be missing.

Links

Table of n, a(n) for n=1..9.

Maple

isA123181 := proc(m)
    A047994(m) ;
    modp(A049060(m)*A034448(m), %*m) = 0 ;
end proc:
for m from 1 do
    if isA123181(m) then
        printf("%a, \n", m) ;
    end if;
end do: # R. J. Mathar, Sep 04 2018

Crossrefs

Cf. A123182, A049060, A034448, A047994.

Sequence in context: A280215 A015103 A282373 * A281932 A074656 A233108

Adjacent sequences: A123178 A123179 A123180 * A123182 A123183 A123184

Keyword

nonn,more

Author

Yasutoshi Kohmoto, Oct 03 2006

Extensions

1 preprended by R. J. Mathar, Sep 04 2018

Status

approved