A339681 Larger of amicable pair a < b such that the ratio of their number of divisors d(a)/d(b) sets a new record.

284, 365084, 2062570, 75866014, 176374564, 11698280566, 33269758575, 1003691825703, 1014479274802, 154378742017851, 4431391475513830, 10007834494951772, 16164656139746247464, 44908741933335600957

Offset: 1

Author

Amiram Eldar, Dec 12 2020

Keywords

• nonn
• more

Comments

The terms are ordered according to their lesser counterparts (A339680).

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

Links

• Sergei Chernykh, Amicable pairs list.

Crossrefs

Cf. A000005, A002025, A002046, A063990, A328063, A339680.

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, {n, m}]) > rm, rm = r; AppendTo[seq, m]], {n, 1, 10^7}]; seq