login
A123181
Numbers such that (-1)Sigma(m)*UnitarySigma(m)= k*UnitaryPhi(m)*m for some integer k.
1
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.
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
KEYWORD
nonn,more
AUTHOR
Yasutoshi Kohmoto, Oct 03 2006
EXTENSIONS
1 preprended by R. J. Mathar, Sep 04 2018
STATUS
approved