OFFSET
1,8
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
MAPLE
for n from 1 to 300 do s := 0: for j from 2 to n-1 do if isprime(j) then else if n mod j = 0 then s := s+j fi; fi: od: printf(`%d, `, s) od:
MATHEMATICA
Join[{0}, Table[Total[Select[Most[Rest[Divisors[n]]], !PrimeQ[#]&]], {n, 2, 90}]] (* Harvey P. Dale, Oct 25 2011 *)
a[n_] := DivisorSigma[1, n] - Plus @@ FactorInteger[n][[;; , 1]] - If[PrimeQ[n], 0, n] - 1; a[1] = 0; Array[a, 100] (* Amiram Eldar, Jun 20 2022 *)
PROG
(Haskell)
a060278 1 = 0
a060278 n = sum $ filter ((== 0) . a010051) $ tail $ a027751_row n
-- Reinhard Zumkeller, Apr 05 2013
(PARI) a(n) = sumdiv(n, d, if ((d<n) && (d>1) && !isprime(d), d)); \\ Michel Marcus, Jan 13 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jack Brennen, Mar 28 2001
EXTENSIONS
More terms from James A. Sellers and Matthew Conroy, Mar 29 2001
STATUS
approved