A086059 Sum of first n 7-almost primes.

128, 320, 608, 928, 1360, 1808, 2288, 2936, 3608, 4312, 5032, 5832, 6664, 7636, 8644, 9700, 10780, 11868, 12988, 14188, 15404, 16652, 18110, 19582, 21094, 22662, 24246, 25866, 27498, 29178, 30938, 32738, 34562, 36418, 38290, 40274, 42274, 44354

Offset: 1

Author

Shyam Sunder Gupta, Aug 24 2003

Keywords

• easy
• nonn

Comments

Elements in this sequence can themselves be 7-almost primes. a(1) = 128 = 2^7. Also a 7-Brilliant number. a(2) = 320 = 2^6 * 5. Also a 7-Brilliant number. Does this happen infinitely often? - Jonathan Vos Post, Dec 11 2004

Examples

			a(2)=320 because sum of first two 7-almost primes i.e. 128+192 is 320.
		

Programs

Mathematica

Accumulate[Select[Range[2500],PrimeOmega[#]==7&]] (* Harvey P. Dale, Oct 18 2018 *)