cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

284, 365084, 2062570, 75866014, 176374564, 11698280566, 33269758575, 1003691825703, 1014479274802, 154378742017851, 4431391475513830, 10007834494951772, 16164656139746247464, 44908741933335600957
Offset: 1

Views

Author

Amiram Eldar, Dec 12 2020

Keywords

Comments

The terms are ordered according to their lesser counterparts (A339680).
The terms were calculated using data from Chernykh's site.

Crossrefs

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
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