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A273016 Ramanujan's largely composite numbers having 5 as the greatest prime divisor. 5
10, 20, 30, 60, 90, 120, 180, 240, 360, 480, 540, 600, 720, 1080, 1440, 2160, 4320 (list; graph; refs; listen; history; text; internal format)
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: A127993 A135557 A093037 * 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

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Last modified December 12 22:06 EST 2019. Contains 329963 sequences. (Running on oeis4.)