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A086059 Sum of first n 7-almost primes. 0

%I #7 Oct 18 2018 22:44:47

%S 128,320,608,928,1360,1808,2288,2936,3608,4312,5032,5832,6664,7636,

%T 8644,9700,10780,11868,12988,14188,15404,16652,18110,19582,21094,

%U 22662,24246,25866,27498,29178,30938,32738,34562,36418,38290,40274,42274,44354

%N Sum of first n 7-almost primes.

%C 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

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

%t Accumulate[Select[Range[2500],PrimeOmega[#]==7&]] (* _Harvey P. Dale_, Oct 18 2018 *)

%K easy,nonn

%O 1,1

%A _Shyam Sunder Gupta_, Aug 24 2003

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Last modified April 25 08:27 EDT 2024. Contains 371964 sequences. (Running on oeis4.)