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A292714
Composite numbers k such that phi(x) = psi(k)*phi(k) has no solution.
0
2197, 4934, 5386, 7606, 10774, 11434, 15212, 15214, 15634, 16294, 17146, 18134, 18374, 18994, 19466, 20134, 20362, 23194, 23451, 24051, 24874, 25526, 25934, 26326, 27411, 27561, 27994, 28486, 28561, 30034, 31334, 31366, 36748, 37834, 38074, 40694, 44054, 46234, 47494, 49834
OFFSET
1,1
COMMENTS
Or composite numbers k such that A007434(k) is not a totient number (A002202).
Prime power terms are 13^3, 13^4, 353^2, 457^2, 733^2, 877^2, 997^2, ...
EXAMPLE
4934 = 2*2467 is a term because psi(4934)*phi(4934) = (2^2 - 1)*(2467^2 - 1) = 2^3*3^3*137*617 is not a totient number (A002202).
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan, Sep 21 2017
STATUS
approved