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A319937 Unitary sociable numbers of order 10. 3

%I #7 Oct 02 2018 11:32:33

%S 525150234,527787366,528544218,553128198,612951066,675192294,

%T 735821562,982674438,998151162,998151174,5251502340,5277873660,

%U 5285442180,5531281980,6129510660,6751922940,7358215620,9826744380,9981511620,9981511740

%N Unitary sociable numbers of order 10.

%H J. O. M. Pedersen, <a href="http://web.archive.org/web/20130731050921/http://amicable.homepage.dk/knwnux.htm">Known Unitary Sociable Numbers of order different from four</a> [Via Internet Archive Wayback-Machine]

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/UnitarySociableNumbers.html">Unitary Sociable Numbers</a>

%H J. O. M. Pedersen, <a href="/A319937/a319937.txt">Order 10 cycles</a>

%o (PARI) f(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)) - n;

%o isok10(n) = iferr(f(f(f(f(f(f(f(f(f(f(n)))))))))) == n, E, 0);

%o isok5(n) = iferr(f(f(f(f(f(n))))) == n, E, 0);

%o isok2(n) = iferr(f(f(n)) == n, E, 0);

%o isok1(n) = iferr(f(n) == n, E, 0);

%o isok(n) = isok10(n) && !isok1(n) && !isok2(n) && !isok5(n);

%Y Cf. A063919 (sum of proper unitary divisors).

%Y Cf. A002827 (unitary perfect), A063991 (unitary amicable).

%Y Cf. A097024 (order 5), A319917 (order 6), A097030 (order 14).

%K nonn,more

%O 1,1

%A _Michel Marcus_, Oct 02 2018

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Last modified August 27 03:11 EDT 2024. Contains 375462 sequences. (Running on oeis4.)