

A122839


Numbers such that Sigma(m)*UnitarySigma(m)= k*UnitaryPhi(m)^2, for some integer k.


1



1, 2, 3, 6, 14, 15, 30, 35, 42, 60, 70, 78, 105, 190, 210, 312, 357, 418, 570, 714, 910, 1045, 1254, 1428, 2090, 2730, 3135, 3640, 4522, 4674, 5278, 6270, 10659, 10920, 12441, 13566, 14630, 15834, 16770, 18696, 20026, 21318, 23374, 24871, 24882, 24969, 25070, 25714, 27170
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OFFSET

1,2


COMMENTS

Terms which are squarefree appear on A121556.


LINKS

Table of n, a(n) for n=1..49.


MAPLE

isA122839 := proc(m)
A047994(m) ;
modp(numtheory[sigma](m)*A034448(m), %^2) = 0 ;
end proc:
for m from 1 do
if isA122839(m) then
printf("%a, \n", m) ;
end if;
end do: # R. J. Mathar, Sep 04 2018


PROG

(PARI) isok(m) = ((sigma(m)*usigma(m)) % uphi(m)^2) == 0; \\ Michel Marcus, Jan 24 2019


CROSSREFS

Cf. A034448, A047994, A121556.
Sequence in context: A146000 A134737 A030733 * A258077 A121556 A123041
Adjacent sequences: A122836 A122837 A122838 * A122840 A122841 A122842


KEYWORD

nonn


AUTHOR

Yasutoshi Kohmoto, Oct 23 2006


EXTENSIONS

More terms from Michel Marcus, Jan 24 2019


STATUS

approved



