|
|
A072983
|
|
Denominator of b(n)=sum (k'<=n,1/k') where k' denotes the squarefree numbers.
|
|
2
|
|
|
1, 2, 6, 6, 30, 5, 35, 35, 35, 70, 770, 770, 10010, 5005, 15015, 15015, 255255, 255255, 4849845, 4849845, 1616615, 3233230, 74364290, 74364290, 74364290, 37182145, 37182145, 37182145, 1078282205, 6469693230, 200560490130, 200560490130
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
b(n) was used by Niven in the 1970's for an alternative proof of the divergence of the sum of reciprocals of the primes.
|
|
LINKS
|
|
|
PROG
|
(PARI) a(n)=denominator(sum(k=1, n, issquarefree(k)/k))
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,frac,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|