login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A positive integer k is included if d(k) = d(k+1) * d(k+2), where d(k) is the number of divisors of k.
4

%I #15 Jul 17 2019 07:36:37

%S 96,105,165,216,280,315,345,357,408,465,522,552,561,616,624,640,696,

%T 744,760,837,861,885,920,924,945,990,1032,1056,1128,1185,1281,1302,

%U 1368,1386,1416,1464,1560,1640,1785,1830,1860,1905,1950,2037,2142,2184,2296

%N A positive integer k is included if d(k) = d(k+1) * d(k+2), where d(k) is the number of divisors of k.

%C Terms calculated by _M. F. Hasler_.

%H Amiram Eldar, <a href="/A175116/b175116.txt">Table of n, a(n) for n = 1..10000</a>

%t Transpose[Select[Partition[Range[3000],3,1],DivisorSigma[0,First[#]]== DivisorSigma[0,Last[#]]DivisorSigma[0,#[[2]]]&]][[1]] (* _Harvey P. Dale_, Apr 08 2011 *)

%Y Cf. A000005, A175115, A145470.

%K nonn

%O 1,1

%A _Leroy Quet_, Feb 13 2010