OFFSET
0,4
COMMENTS
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
EXAMPLE
a(7) = d(7*8/2) = d(28) = d(2*14) = d(2)*14 + 2*d(14) =
= 1*14 + 2*d(2*7) = 14 + 2*(2*d(7) + d(2)*7) =
= 14 + 2*(2*1 + 1*7) = 14 + 2*9 = 14 + 18 = 32;
where d(n) = A003415(n)
with d(1)=0, d(prime)=1 and d(m*n)=d(m)*n+m*d(n).
PROG
(Haskell)
a068312 = a003415 . a000217 -- Reinhard Zumkeller, May 26 2015
(Python)
from sympy import factorint
def A068312(n): return 0 if n <= 1 else ((n+1)*sum((n*e//p for p, e in factorint(n).items()))+ sum(((n+1)*e//p for p, e in factorint(n+1).items()))*n - (n*(n+1)//2))//2 # Chai Wah Wu, Jun 24 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Feb 25 2002
EXTENSIONS
a(0)=0 prepended by Reinhard Zumkeller, May 26 2015
STATUS
approved