OFFSET
0,2
COMMENTS
a(n)/A072045(n) -> (Pi^2)/6 (Leonhard Euler, 1748).
REFERENCES
M. Sigg: "Pi" p. 191 in Lexikon der Mathematik, Band 4, Spektrum Verlag, 2002.
EXAMPLE
For the first 3 primes: 2,3,5: (2^2/(2^2-1))*(3^2/(3^2-1))*(5^2/(5^2-1)) = (4/3)*(9/8)*(25/24) = (4*9*25)/(3*8*24) = 25/16, therefore a(3)=25;
a(10)/A072045(10)=86285158710179/52836150804480=1.63307049.
MATHEMATICA
Numerator/@Rest[FoldList[Times, 1, #/(#-1)&/@(Prime[Range[15]]^2)]] (* Harvey P. Dale, May 03 2011 *)
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Reinhard Zumkeller, Jun 09 2002
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, May 11 2024
STATUS
approved