A325847 Lesser of exponentially-odd amicable numbers pair: numbers m < k such that m = s(k) and k = s(m), where s(k) is the sum of proper exponential-odd divisors of k.

366, 3864, 16104, 16536, 59808, 71904, 142290, 142310, 196248, 198990, 240312, 326424, 341088, 348840, 366792, 520608, 664608, 704352, 753312, 912072, 1077890, 1156870, 1184490, 1511930, 1669910, 1805490, 1863456, 1936776, 2195640, 2236570, 2517480, 2686440

Offset

1,1

Comments

The sum of proper exponential-odd divisors of k is A033634(k) - k if k is exponentially odd (A268335), or A033634(k) if not.

The larger counterparts are in A325848.

Links

Amiram Eldar, Table of n, a(n) for n = 1..789 (terms below 10^10)

Mathematica

f[e_] := If[OddQ[e], e + 2, e + 1]; fun[p_, e_] := 1 + (p^f[e] - p)/(p^2 - 1); a[1] = 1; a[n_] := Times @@ (fun @@@ (fct = FactorInteger[n])) - If[AllTrue[fct[[;; , 2]], OddQ], n, 0]; s = {}; Do[m = a[n]; If[m > n && a[m] == n, AppendTo[s, n]], {n, 1, 10^5}]; s

Crossrefs

Cf. A033289, A033634, A268335, A325848.

Sequence in context: A350471 A249704 A260281 * A279982 A286793 A079493

Adjacent sequences: A325844 A325845 A325846 * A325848 A325849 A325850

Keyword

nonn

Author

Amiram Eldar, Sep 07 2019

Status

approved