A241650 - OEIS

%I #18 Dec 19 2024 06:16:14

%S 6,22152,35724,125892,132444,146484,166764,182052,192504,202332,

%T 239304,242580,248664,267852,291252,300612,375492,375804,434772,

%U 460044,494364,536952,547992,550524,618852,628212,646668,707304,708984,752232,777852,824304,828984

%N Numbers m such that the GCD of the x's that satisfy sigma(x) = m is 5.

%H Amiram Eldar, <a href="/A241650/b241650.txt">Table of n, a(n) for n = 1..5000</a>

%H Max Alekseyev, <a href="https://oeis.org/wiki/User:Max_Alekseyev/gpscripts">PARI/GP Scripts for Miscellaneous Math Problems</a> (invphi.gp).

%e Only sigma(5) = 6, with gcd(5) = 5, so 6 is in the sequence.

%e Also, sigma(12735) = sigma(18455) = 22152, and gcd(12735, 18455) = 5, hence 22152 is in the sequence.

%o (PARI) is(k) = gcd(invsigma(k)) == 5; \\ _Amiram Eldar_, Dec 19 2024, using _Max Alekseyev_'s invphi.gp

%Y Cf. A000203, A240667, A241625, A241646, A241647, A241648, A241649.

%K nonn

%O 1,1

%A _Michel Marcus_, Apr 26 2014