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A222712 Record values of gcd(sigma(n), phi(n)) (A009223). 2


%S 1,2,4,6,8,24,48,72,120,192,240,336,720,960,1440,1872,2016,2880,3360,

%T 4032,5760,6720,6912,7392,8640,10080,17280,20160,34560,40320,44352,

%U 60480,69120,74880,95040,96768,100800,120960,134784,201600,241920,322560,354816,411840,483840

%N Record values of gcd(sigma(n), phi(n)) (A009223).

%C RECORDS transform of A009223.

%H Donovan Johnson, <a href="/A222712/b222712.txt">Table of n, a(n) for n = 1..500</a>

%H N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> (The RECORDS transform returns both the high-water marks and the places where they occur).

%o (PARI) mg=0;for(x=1,1000000,g=A009223(x);if(g>mg,print1(g", ");mg=g))

%Y Cf. A009223, A222711 (indexes where these records are attained).

%K nonn

%O 1,2

%A _Phil Carmody_, Mar 01 2013

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Last modified December 7 22:29 EST 2019. Contains 329850 sequences. (Running on oeis4.)