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A045613 Minimal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements. 4

%I #22 Feb 19 2019 04:43:49

%S 33,105,110,208,268,455,695,812,1609,1808,1892,1913,2096,2145,3123,

%T 3272,3867,4129,5424,5600,5916,6524,6783,7069,7119,7875,9716,10506,

%U 11088,11265,11552,12324,12892,12939,13712,14210,15429,15762,17252,17490,18368,19616

%N Minimal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.

%H Amiram Eldar, <a href="/A045613/b045613.txt">Table of n, a(n) for n = 1..40410</a> (terms below 10^10, terms 1..1000 from Donovan Johnson)

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

%F usigma(usigma(a)) = usigma(usigma(b)) = a+b where a<b and usigma(n) = A034448(n) is the sum of the unitary divisors of n. This sequence gives the values of a; A045614 gives the values of b.

%t usigma[n_] := If[n == 1, 1, Times @@ (1 + Power @@@ FactorInteger[n])]; u[n_] := usigma[usigma[n]] - n; s = {}; Do[m = u[n]; If[m > n && u[m] == n, AppendTo[s, n]], {n, 1, 10000}]; s (* _Amiram Eldar_, Feb 18 2019 *)

%Y Cf. A045614, A034448.

%K nonn

%O 1,1

%A _Yasutoshi Kohmoto_

%E Edited by _Dean Hickerson_, Nov 06 2006

%E Offset corrected by _Donovan Johnson_, Jul 26 2012

%E More terms from _Amiram Eldar_, Feb 18 2019

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Last modified April 18 15:48 EDT 2024. Contains 371780 sequences. (Running on oeis4.)