A387643 Difference between larger and smaller term of n-th psi-amicable pair, sorted by the smaller members from A323329.

220, 440, 940, 880, 1100, 1880, 1760, 1652, 2200, 340, 3760, 1780, 4700, 3520, 3304, 4400, 680, 7520, 5500, 3560, 9400, 7040, 6608, 8800, 1360, 15040, 11000, 8780, 7120, 1700, 18800, 11564, 14080, 13216, 8900, 23500, 17600, 2720, 30080, 22000, 26420, 17560, 14240, 3400, 37600, 8610

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Formula

a(n) = A323330(n) - A323329(n).

Example

a(7) = A323330(7) - A323329(7) = 12400 - 10640 = 220.

Mathematica

psi[n_] := n * Times @@ (1 + 1/FactorInteger[n][[;; , 1]]); psi[1] = 1; t[n_] := psi[n] - n; seq[max_] := Module[{s = {}, n}, Do[n = t[m]; If[n > m && t[n] == m, AppendTo[s, n - m]], {m, 1, max}]; s]; seq[200000] (* Amiram Eldar, Sep 05 2025 *)

Crossrefs

Cf. A001615, A066539, A323329, A323330, A387641.

Sequence in context: A287011 A333929 A157107 * A175738 A260203 A184543

Adjacent sequences: A387640 A387641 A387642 * A387644 A387645 A387646

Keyword

nonn

Author

S. I. Dimitrov, Sep 04 2025

Status

approved