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

1,1

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

Links

Table of n, a(n) for n=1..38.

Example

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

Mathematica

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

Crossrefs

Sequence in context: A045053 A234877 A229360 * A220582 A203449 A195090

Adjacent sequences: A086056 A086057 A086058 * A086060 A086061 A086062

Keyword

easy,nonn

Author

Shyam Sunder Gupta, Aug 24 2003

Status

approved