|
%I #15 Mar 16 2019 16:03:39
%S 7336455,41337555,110691295,108212055,154646206,313439511,6400149855,
%T 9971007915,10049576691,9849706755,12125842995,12180547995,
%U 14064001666,18225635506,26623431835,20500208806,23746912995,23952459706,43137954706,56039259255,99517314526,125782774755
%N Larger of augmented unitary amicable pair.
%C A pair m < n is an augmented unitary amicable pair if usigma(m) = usigma(n) = m + n - 1, where usigma(n) is the sum of unitary divisors of n (A034460).
%C The terms are ordered according to their lesser counterparts (A306872).
%H Amiram Eldar, <a href="/A306873/b306873.txt">Table of n, a(n) for n = 1..27</a> (terms with lesser member below 10^12, from David Moews's site).
%H David Moews, <a href="http://djm.cc/amicable.html">Perfect, amicable and sociable numbers</a>
%H J. O. M. Pedersen, <a href="http://62.198.248.44/aliquot/tables.htm">Tables of Aliquot Cycles</a>
%e 7336455 is in the sequence since it is the larger of the amicable pair (6224890, 7336455): usigma(6224890) = usigma(7336455) = 13561344 = 6224890 + 7336455 - 1.
%t us[n_] := Times @@ (1 + Power @@@ FactorInteger[n]) - n; s={}; Do[m = us[n] + 1; If[m > n && us[m] == n - 1, AppendTo[s, m]], {n, 1, 10^9}]; s
%Y Cf. A002953, A015630, A034460, A126175, A306872.
%K nonn
%O 1,1
%A _Amiram Eldar_, Mar 14 2019
|
