OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
a(24) = 14 because tau(24) = 8 and the sum of the 3 even divisors {2, 4, 8} is 14.
MATHEMATICA
Table[Total[Select[Divisors[DivisorSigma[0, n]], EvenQ[ # ]&]], {n, 74}]
PROG
(PARI) a(n)=sumdiv(sigma(n, 0), d, (1-d%2)*d);
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 23 2011
EXTENSIONS
Data section extended to 100 terms by Antti Karttunen, May 28 2017
STATUS
approved