A045614 Maximal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.

35, 155, 142, 224, 272, 601, 1033, 956, 1847, 2512, 3004, 2407, 2224, 3055, 3357, 4288, 5637, 4511, 7536, 5824, 6460, 7756, 8637, 7619, 8721, 7965, 14044, 14974, 16992, 13503, 14656, 14508, 14108, 18261, 22576, 17542, 16251, 20638, 18108, 29960, 27328, 24736

Offset: 1

Author

Yasutoshi Kohmoto

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..40410 (terms below 10^10, terms 1..1000 from Donovan Johnson)
• Eric Weisstein's World of Mathematics, Super Unitary Amicable Pair

Crossrefs

Cf. A045613, A034448.

Programs

Mathematica

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, m]], {n, 1, 10000}]; s (* Amiram Eldar, Feb 18 2019 *)

Formula

usigma(usigma(a)) = usigma(usigma(b)) = a+b where aA034448(n) is the sum of the unitary divisors of n. This sequence gives the values of b; A045613 gives the values of a.

Extensions

Edited by Dean Hickerson, Nov 06 2006

Offset corrected by Donovan Johnson, Jul 26 2012

More terms from Amiram Eldar, Feb 18 2019