

A306873


Larger of augmented unitary amicable pair.


2



7336455, 41337555, 110691295, 108212055, 154646206, 313439511, 6400149855, 9971007915, 10049576691, 9849706755, 12125842995, 12180547995, 14064001666, 18225635506, 26623431835, 20500208806, 23746912995, 23952459706, 43137954706, 56039259255, 99517314526, 125782774755
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OFFSET

1,1


COMMENTS

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).
The terms are ordered according to their lesser counterparts (A306872).


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..27 (terms with lesser member below 10^12, from David Moews's site).
David Moews, Perfect, amicable and sociable numbers
J. O. M. Pedersen, Tables of Aliquot Cycles


EXAMPLE

7336455 is in the sequence since it is the larger of the amicable pair (6224890, 7336455): usigma(6224890) = usigma(7336455) = 13561344 = 6224890 + 7336455  1.


MATHEMATICA

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


CROSSREFS

Cf. A002953, A015630, A034460, A126175, A306872.
Sequence in context: A116236 A116259 A158256 * A269220 A268406 A302135
Adjacent sequences: A306870 A306871 A306872 * A306874 A306875 A306876


KEYWORD

nonn


AUTHOR

Amiram Eldar, Mar 14 2019


STATUS

approved



