A076581 Triangular numbers which are 7-almost primes.

2080, 4560, 8128, 9180, 10296, 10440, 12720, 12880, 15400, 18336, 18528, 21528, 23220, 23436, 29403, 29646, 37128, 39060, 43956, 52326, 56280, 61425, 64980, 67896, 70500, 81810, 82215, 86320, 86736, 93096, 93528, 100576, 103740, 105570

Offset

1,1

Links

Table of n, a(n) for n=1..34.

Example

a(1)=2080, 2080 is a triangular number and 2080=2*2*2*2*2*5*13 i.e. is a product of 7 prime factors so is 7-almost prime.

Crossrefs

Sequence in context: A249654 A180921 A270537 * A183675 A178272 A194605

Adjacent sequences: A076578 A076579 A076580 * A076582 A076583 A076584

Keyword

base,easy,nonn

Author

Shyam Sunder Gupta, Oct 19 2002

Status

approved