cp's OEIS Frontend

A173969 Sums of three consecutive numbers each of which is the product of two distinct primes and each of which has no exponent greater than one for either of its two prime factors.

%I A173969 #9 Jul 22 2025 07:51:29
%S A173969 102,258,282,426,606,642,654,906,1182,1338,1902,2094,2766,3126,3414,
%T A173969 3786,4038,4206,4926,5286,5514,5682,5826,5946,6306,6546,6654,6918,
%U A173969 7086,7302,7386,7554,7926,8166,8202,9294,10158,10806,11082,11598,11706,11874
%N A173969 Sums of three consecutive numbers each of which is the product of two distinct primes and each of which has no exponent greater than one for either of its two prime factors.
%C A173969 Terms that included in A173968 but Not included in the current seq are: 366,2526,18726,220326,430926,637566,814326,..
%C A173969 The number of prime factors of each of the 3 consecutive numbers must be 2 even when counted with multiplicity. - _Harvey P. Dale_, Aug 14 2021
%H A173969 Harvey P. Dale, <a href="/A173969/b173969.txt">Table of n, a(n) for n = 1..1000</a>
%t A173969 f[n_]:=Last/@FactorInteger[n]=={1,1};lst={};Do[If[f[n],If[f[n+1]&&f[n+2],AppendTo[lst,3*n+3]]],{n,8!}];lst2=lst
%t A173969 Total[#]+Mean[#]&/@SequencePosition[Table[If[PrimeNu[n]==PrimeOmega[n]==2,1,0],{n,4000}],{1,1,1}] (* _Harvey P. Dale_, Aug 14 2021 *)
%Y A173969 Cf. A173966, A173967, A173968
%K A173969 nonn
%O A173969 1,1
%A A173969 _Vladimir Joseph Stephan Orlovsky_, Mar 03 2010
%E A173969 Definition clarified by _Harvey P. Dale_, Aug 14 2021