A168472 Partial sums of products of two distinct primes (A006881).

6, 16, 30, 45, 66, 88, 114, 147, 181, 216, 254, 293, 339, 390, 445, 502, 560, 622, 687, 756, 830, 907, 989, 1074, 1160, 1247, 1338, 1431, 1525, 1620, 1726, 1837, 1952, 2070, 2189, 2311, 2434, 2563, 2696, 2830, 2971, 3113, 3256, 3401, 3547, 3702, 3860, 4019

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

N:= 1001: # to get all a(n) where A006881(n) < N
Primes:= select(isprime, [2, seq(2*k+1, k=1..floor(N/2))]):
L:= sort(convert({seq(seq(p*q, q=Primes[1..ListTools:-BinaryPlace(Primes, N/p)]), p=Primes)} minus {seq(p^2, p=Primes)}, list)):
ListTools:-PartialSums(L); # Robert Israel, Apr 29 2018

Mathematica

f[n_]:=Last/@FactorInteger[n]=={1, 1}; s=0; lst={}; Do[If[f[n], AppendTo[lst, s+=n]], {n, 6!}]; lst
With[{nn=50}, Take[Accumulate[Union[Times@@@Subsets[Prime[Range[nn]], {2}]]], nn]] (* Harvey P. Dale, Aug 08 2013 *)

Crossrefs

Sequence in context: A164052 A264938 A350011 * A054000 A113742 A102214

Adjacent sequences: A168469 A168470 A168471 * A168473 A168474 A168475

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Nov 26 2009

Status

approved