A387885 Product of smaller and larger term of n-th psi-amicable pair, sorted by the smaller members from A323329.

2061500, 8246000, 18441500, 32984000, 51537500, 73766000, 131936000, 145630940, 206150000, 228585500, 295064000, 377121500, 461037500, 527744000, 582523760, 824600000, 914342000, 1180256000, 1288437500, 1508486000, 1844150000, 2110976000, 2330095040, 3298400000, 3657368000, 4721024000

Offset

1,1

Comments

Are all terms psi-abundant (A387893)?

All the terms are psi-abundant since all the terms of A323329 are by definition psi-abundant, and any positive multiple of a psi-abundant number is also psi-abundant. - Amiram Eldar, Sep 11 2025

Links

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

Formula

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

Example

a(7) = A323329(7) * A323330(7) = 10640 * 12400 = 131936000.

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[10^5] (* Amiram Eldar, Sep 11 2025 *)

Crossrefs

Cf. A001615, A180202, A323329, A323330, A387893.

Sequence in context: A206667 A251512 A113568 * A186915 A186907 A186906

Adjacent sequences: A387882 A387883 A387884 * A387886 A387887 A387888

Keyword

nonn

Author

S. I. Dimitrov, Sep 11 2025

Status

approved