A076580 Triangular numbers which are 6-almost primes.

528, 1176, 4656, 4950, 5460, 6216, 7140, 7260, 7875, 11628, 13041, 14196, 15576, 17766, 17955, 19110, 20100, 21736, 24976, 26796, 28680, 28920, 31878, 33930, 34980, 37950, 44850, 45150, 46056, 46360, 49770, 56616, 58653, 58996, 59340

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

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.

Mathematica

Select[Accumulate[Range[400]], PrimeOmega[#]==6&] (* Harvey P. Dale, May 19 2019 *)

Crossrefs

Sequence in context: A157475 A373285 A158365 * A304512 A037944 A282096

Adjacent sequences: A076577 A076578 A076579 * A076581 A076582 A076583

Keyword

base,easy,nonn

Author

Shyam Sunder Gupta, Oct 19 2002

Status

approved