A086294 Sum of distinct prime factors of 7-smooth numbers.

0, 2, 3, 2, 5, 5, 7, 2, 3, 7, 5, 9, 8, 2, 5, 7, 10, 5, 5, 3, 9, 10, 2, 12, 5, 7, 12, 8, 5, 7, 7, 5, 9, 10, 10, 2, 14, 5, 8, 7, 3, 12, 10, 5, 9, 7, 15, 5, 9, 10, 5, 12, 2, 8, 14, 5, 10, 10, 7, 5, 12, 12, 10, 10, 5, 9, 7, 17, 5, 9, 8, 10, 3, 12, 7, 12, 2, 10, 14, 5, 12, 10, 15, 7, 5, 12, 7

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A008472(A002473(n)).

Mathematica

sumPrimes[1] = 0; sumPrimes[n_] := Plus @@ First[Transpose[FactorInteger[n]]]; sumPrimes/@Select[Range[500], Max[Transpose[FactorInteger[#]][[1]]] <= 7 &] (* Amiram Eldar, Jan 06 2020 *)
dpf7[n_]:=Module[{fi=FactorInteger[n][[All, 1]]}, If[Max[fi]<11, Total[ fi], Nothing]]; Join[{0}, Array[dpf7, 400, 2]] (* Harvey P. Dale, Feb 26 2022 *)

Crossrefs

Cf. A002473, A008472, A086288, A086293, A086295.

Sequence in context: A367476 A141346 A095402 * A361632 A075860 A361630

Adjacent sequences: A086291 A086292 A086293 * A086295 A086296 A086297

Keyword

nonn

Author

Reinhard Zumkeller, Jul 15 2003

Status

approved