A273016 Ramanujan's largely composite numbers having 5 as the greatest prime divisor.

10, 20, 30, 60, 90, 120, 180, 240, 360, 480, 540, 600, 720, 1080, 1440, 2160, 4320

Offset

1,1

Comments

By the theorem in comment in A273015, the sequence is finite.

Links

Table of n, a(n) for n=1..17.

Mathematica

a = {}; b = {0}; Do[If[# >= Max@ b, AppendTo[a, k] && AppendTo[b, #]] &@ DivisorSigma[0, k], {k, 10^7}]; Select[a, FactorInteger[#][[-1, 1]] == 5 &] (* Michael De Vlieger, May 13 2016 *)

Crossrefs

Cf. A067128, A273015.

Sequence in context: A135557 A093037 A355695 * A269238 A279420 A274051

Adjacent sequences: A273013 A273014 A273015 * A273017 A273018 A273019

Keyword

nonn,fini,full

Author

Vladimir Shevelev and Peter J. C. Moses, May 13 2016

Status

approved