OFFSET
1,1
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..10000
FORMULA
From Amiram Eldar, Dec 16 2022: (Start)
Sum_{k=1..n} a(k) = (55*Pi^2/84) * n^2 + O(n*log(n)). (End)
EXAMPLE
For n = 3, the divisors of 3*7 are {1, 3, 7, 21}. Now, 1 + 3 + 7 + 21 = 32. So, a(3) = 32. - Indranil Ghosh, Feb 28 2017
MATHEMATICA
Table[DivisorSigma[1, 7n], {n, 1, 54}] (* Indranil Ghosh, Feb 28 2017 *)
PROG
(PARI) a(n) = sigma(7*n) \\ Indranil Ghosh, Feb 28 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 28 2017
STATUS
approved