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A057022
a(n) = floor((sum of divisors of n) / (number of divisors of n)), or floor(sigma_1(n)/sigma_0(n)).
6
1, 1, 2, 2, 3, 3, 4, 3, 4, 4, 6, 4, 7, 6, 6, 6, 9, 6, 10, 7, 8, 9, 12, 7, 10, 10, 10, 9, 15, 9, 16, 10, 12, 13, 12, 10, 19, 15, 14, 11, 21, 12, 22, 14, 13, 18, 24, 12, 19, 15, 18, 16, 27, 15, 18, 15, 20, 22, 30, 14, 31, 24, 17, 18, 21, 18, 34, 21, 24, 18
OFFSET
1,3
COMMENTS
Floor of mean of divisors of n. - Jon E. Schoenfield, Dec 24 2016
LINKS
FORMULA
a(n) = (A000203(n) - A054025(n))/A000005(n).
EXAMPLE
a(4)=2 since the 3 divisors of 4 are 1, 2 and 4 and floor((1 + 2 + 4)/3) = floor(7/3) = 2.
MATHEMATICA
Floor[Table[Total[Divisors[n]]/Length[Divisors[n]], {n, 20}]] (* Daniel Jolly, Nov 15 2014 *)
Table[Floor[DivisorSigma[1, n]/DivisorSigma[0, n]], {n, 70}] (* Harvey P. Dale, Jan 14 2015 *)
PROG
(Haskell)
a057022 n = a000203 n `div` a000005 n
-- Reinhard Zumkeller, Jan 06 2012
(PARI) a(n) = sigma(n)\numdiv(n); \\ Michel Marcus, Nov 15 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, Jul 21 2000
STATUS
approved