A273018 - OEIS

%I #9 May 21 2016 23:38:52

%S 84,168,336,420,504,630,672,840,1260,1680,2520,3360,3780,4200,5040,

%T 7560,10080,12600,15120,20160,25200,30240,37800,40320,45360,50400,

%U 75600,151200

%N Ramanujan's largely composite numbers having 7 as the greatest prime divisor.

%C By the theorem in A273015, the sequence is finite.

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

%Y Cf. A067128, A273015, A273016.

%K nonn,fini,full

%O 1,1

%A _Vladimir Shevelev_ and _Peter J. C. Moses_, May 13 2016