A002953 - OEIS

%I M5389 #28 Jun 28 2017 02:57:59

%S 126,1260,22302,40446,49308,64530,73962,168730,223020,286500,242730,

%T 429750,365700,548550,618570,827700,739620,827652,932100,1241550,

%U 1099390,1291050,1292570,1241478,1398150,1621500,1669150,1598470,1654212

%N Larger of unitary amicable pair.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H T. D. Noe, <a href="/A002953/b002953.txt">Table of n, a(n) for n = 1..7896</a> (from Pedersen's website)

%H Peter Hagis, Jr., <a href="http://www.jstor.org/stable/2004356">Unitary amicable numbers</a>, Math. Comp., 25 (1971), 915-918.

%H J. M. Pedersen, <a href="http://amicable.homepage.dk/knwnunap.htm">Known Unitary Amicable Pairs</a>

%H J. O. M. Pedersen, <a href="http://amicable.homepage.dk/tables.htm">Tables of Aliquot Cycles</a> [Broken link]

%H J. O. M. Pedersen, <a href="http://web.archive.org/web/20140502102524/http://amicable.homepage.dk/tables.htm">Tables of Aliquot Cycles</a> [Via Internet Archive Wayback-Machine]

%H J. O. M. Pedersen, <a href="/A063990/a063990.pdf">Tables of Aliquot Cycles</a> [Cached copy, pdf file only]

%H Ivars Peterson, <a href="https://www.sciencenews.org/article/amicable-pairs-divisors-and-new-record">Amicable Pairs, Divisors, and a New Record</a>, January 30 2004.

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

%t uDivisors[n_] := Select[Divisors[n], # < n && GCD[#, n/#] == 1 & ]; mate[n_] := If[m = Total[uDivisors[n]]; n == Total[uDivisors[m]], m, 0]; Reap[Do[If[n < (m = mate[n]), Print[m]; Sow[m]], {n, 2, 2000000}]][[2, 1]] (* _Jean-François Alcover_, Jun 12 2012 *)

%Y Cf. A002952, A063991, A111904.

%K nonn,nice

%O 1,1

%A _N. J. A. Sloane_; extended Nov 24 2005