OFFSET
1,1
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 3, 0, 0, 0, -3, 0, 0, 0, 1).
FORMULA
Sum_{n>=1} 1/a(n) = Pi^2/27 (A291050). - Amiram Eldar, Sep 14 2022
MATHEMATICA
Denominator/@(8/(9Range[50]^2)) (* Harvey P. Dale, Mar 15 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul Curtz, Nov 20 2008
EXTENSIONS
Stratified definition, corrected indices, extended, R. J. Mathar, Dec 10 2008
STATUS
approved