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Triangular numbers which are 6-almost primes.
1

%I #6 May 19 2019 16:17:19

%S 528,1176,4656,4950,5460,6216,7140,7260,7875,11628,13041,14196,15576,

%T 17766,17955,19110,20100,21736,24976,26796,28680,28920,31878,33930,

%U 34980,37950,44850,45150,46056,46360,49770,56616,58653,58996,59340

%N Triangular numbers which are 6-almost primes.

%H Harvey P. Dale, <a href="/A076580/b076580.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=528, 528 is a triangular number and 528=2*2*2*2*3*11 i.e. is a product of 6 prime factors so is 6-almost prime.

%t Select[Accumulate[Range[400]],PrimeOmega[#]==6&] (* _Harvey P. Dale_, May 19 2019 *)

%K base,easy,nonn

%O 1,1

%A _Shyam Sunder Gupta_, Oct 19 2002