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%I #21 Sep 16 2023 17:13:00
%S 11,527,923,36859,40549,55309,88519,120139,138301,280579,293501,
%T 313807,529789,719927,2458859,4864117,6191413,6811243,7297877,8402663,
%U 8624107,9487477,10475821,12356441,12940957,13624717,13971229,14869033,15293137
%N Numbers k such that 6*phi(k) = 5*sigma(k).
%C Not all terms are squarefree: a(74) = 137640191 = 13^2 * 89 * 9151. - _Charles R Greathouse IV_, Nov 13 2015
%C Apart from the first term, no terms are divisible by 2, 3, 5, 7, or 11. - _Charles R Greathouse IV_, Nov 13 2015
%H Harry J. Smith and Charles R Greathouse IV, <a href="/A065823/b065823.txt">Table of n, a(n) for n = 1..651</a> (first 70 terms from Smith)
%o (PARI) n=0; for (m=1, 10^9, if (6*eulerphi(m) == 5*sigma(m), write("b065823.txt", n++, " ", m); if (n==70, return))) \\ _Harry J. Smith_, Nov 01 2009
%o (PARI) is(n)=my(f=factor(n)); 6*eulerphi(f)==5*sigma(f) \\ _Charles R Greathouse IV_, Nov 13 2015
%Y Subsequence of A008364.
%Y Cf. A000010, A000203, A065818, A065819, A062699, A065822, A274535(5*sigma(n)).
%K nonn
%O 1,1
%A _Labos Elemer_, Nov 23 2001
%E Terms a(16)-a(29) from _Harry J. Smith_, Nov 01 2009