OFFSET
1,2
COMMENTS
sum(k>=1,1/k^4)=zeta(4)=Pi^4/90
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
FORMULA
lim n ->infinity a(n)/n=C=3, 3....
EXAMPLE
The simple continued fraction for sum(k=1,10,1/k^4) is [1, 12, 5, 3, 1, 2, 10, 12, 1, 2, 4, 2, 2, 2, 1, 7, 11, 1, 1, 2, 5, 2, 2, 4, 3, 1, 1, 1, 2] which contains 29 terms, hence a(10)=29.
MATHEMATICA
Length[ContinuedFraction[#]]&/@Accumulate[1/Range[60]^4] (* Harvey P. Dale, Dec 20 2012 *)
PROG
(PARI) for(n=1, 100, print1(length(contfrac(sum(i=1, n, 1/i^4))), ", "))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 18 2002
STATUS
approved