A387641 Sum of larger and smaller term of n-th psi-amicable pair, sorted by the smaller members from A323329.

2880, 5760, 8640, 11520, 14400, 17280, 23040, 24192, 28800, 30240, 34560, 38880, 43200, 46080, 48384, 57600, 60480, 69120, 72000, 77760, 86400, 92160, 96768, 115200, 120960, 138240, 144000, 155520, 155520, 151200, 172800, 169344, 184320, 193536, 194400, 216000, 230400, 241920

Offset

1,1

Comments

Are all terms psi-abundant (A387893)? The first 1000 terms are.

Links

S. I. Dimitrov, Table of n, a(n) for n = 1..1000

Formula

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

a(n) = A001615(A323329(n)) = A001615(A323330(n)). - Amiram Eldar, Sep 05 2025

Example

a(7) = A323329(7) + A323330(7) = 10640 + 12400 = 23040.

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[120000] (* Amiram Eldar, Sep 05 2025 *)

Crossrefs

Cf. A001615, A180164, A323329, A323330, A387643.

Sequence in context: A175750 A179703 A260369 * A134856 A066407 A184602

Adjacent sequences: A387638 A387639 A387640 * A387642 A387643 A387644

Keyword

nonn

Author

S. I. Dimitrov, Sep 04 2025

Status

approved