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 A259304 Numbers n such that there exists an x!=n that makes {n,n,n,x} an amicable multiset. 9

%I

%S 796320,1205820,1277640,1963080,5154240,8599500,8694000,9022860,

%T 10820880,12149280,15845760,17173800,18023040,19323360,21360240,

%U 22720320,25494480,27052200,27335880,28365480,28574280,28704060,29211000,30329640,30373200,30450420,31433220

%N Numbers n such that there exists an x!=n that makes {n,n,n,x} an amicable multiset.

%C We call the multiset {n,n,n,x} amicable iff sigma(n)=sigma(x)=n+n+n+x.

%C For the x values, see A259305.

%C If the condition x!=n were dropped, the terms from A027687 would also belong here.

%H John Cerkan, <a href="/A259304/b259304.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) isOK(n) = x=sigma(n)-3*n; x>0&x!=n&sigma(x)==3*n+x

%Y Cf. A027687, A259307, A259305, A259302, A259303, A259306, A036471.

%K nonn

%O 1,1

%A _Jeppe Stig Nielsen_, Jun 23 2015

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Last modified March 25 03:28 EDT 2023. Contains 361511 sequences. (Running on oeis4.)