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

Author

Amiram Eldar, Dec 12 2020

Keywords

• nonn
• more

Comments

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

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

Links

• Sergei Chernykh, Amicable pairs list.

Crossrefs

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

Programs

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