A339683 Larger of amicable pair a < b such that the ratio of their number of divisors d(b)/d(a) sets a new record.

284, 1210, 486178, 12361622, 39944086, 6119799324639, 15309719733555, 36680009488425, 20386078790473473, 43160565196326158, 1052608596326926425, 6924667299336450388

Offset

1,1

Comments

The terms are ordered according to their lesser counterparts (A339682).

The terms were calculated using data from Chernykh's site.

Links

Table of n, a(n) for n=1..12.

Sergei Chernykh, Amicable pairs list.

Mathematica

s[n_] := DivisorSigma[1, n] - n; rm = 0; seq = {}; Do[m = s[n]; If[m > n && s[m] == n && (r = Divide @@ DivisorSigma[0, {m, n}]) > rm, rm = r; AppendTo[seq, m]], {n, 1, 10^7}]; seq

Crossrefs

Cf. A000005, A002025, A002046, A063990, A328255, A339682.

Sequence in context: A260087 A002046 A339679 * A343917 A143191 A180220

Adjacent sequences: A339680 A339681 A339682 * A339684 A339685 A339686

Keyword

nonn,more

Author

Amiram Eldar, Dec 12 2020

Status

approved