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

1,1

Comments

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

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

Links

Table of n, a(n) for n=1..14.

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

Crossrefs

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

Sequence in context: A049024 A277771 A093228 * A249954 A043415 A288037

Adjacent sequences: A339678 A339679 A339680 * A339682 A339683 A339684

Keyword

nonn,more

Author

Amiram Eldar, Dec 12 2020

Status

approved