OFFSET
0,2
COMMENTS
Numerators are given in A096949.
FORMULA
a(n)=denominator(A(n)) with the rational number A(n):= sum(((1/3)^(2*k))/(2*k+1), k=0..n) in lowest terms.
EXAMPLE
n=10: A096949(10)/2415766270466835 = 2511722368895123/2415766270466835 = 1.039720770838... approximates 3*arctanh(1/3)= 1.039720770840...
CROSSREFS
KEYWORD
nonn,easy,frac
AUTHOR
Wolfdieter Lang, Jul 16 2004
STATUS
approved