OFFSET
1,2
REFERENCES
Handbook of Number Theory, D. S. Mitrinovic et al., Kluwer, Section IV.1.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
K. Alladi and P. Erdős, On an additive arithmetic function, Pacific J. Math., Volume 71, Number 2 (1977), 275-294. MR 0447086 (56 #5401).
A. E. Brouwer, Two number theoretic sums, Stichting Mathematisch Centrum. Zuivere Wiskunde, Report ZW 19/74 (1974): 3 pages. [Cached copy, included with the permission of the author]
FORMULA
a(n) = Pi^2/12 * n^2/log n + O(n^2/log^2 n). [See Mitrinovic et al.] - Charles R Greathouse IV, Feb 19 2014
MATHEMATICA
Accumulate[Prepend[Table[FactorInteger[n][[-1, 1]], {n, 2, 100}], 1]] (* Harvey P. Dale, Jun 11 2011 *)
PROG
(Haskell)
a046670 n = a046670_list !! (n-1)
a046670_list = scanl1 (+) a006530_list -- Reinhard Zumkeller, Jun 15 2013
(PARI) gpf(n)=if(n<4, n, n=factor(n)[, 1]; n[#n])
a(n)=sum(k=1, n, gpf(k)) \\ Charles R Greathouse IV, Feb 19 2014
CROSSREFS
KEYWORD
nonn,nice,easy
AUTHOR
EXTENSIONS
More terms from James A. Sellers
STATUS
approved