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A376049
a(n) is the denominator of the sum S(n) defined in A376048.
4
1, 4, 20, 1620, 2626020, 34479907828020, 10699776394458828344981911620, 228970429782836729250563232145698649718622958323963960420, 314564746289621790478499809054644383073494124885364231904506529162346525698245870188461228508418377184391923418820
OFFSET
0,2
LINKS
FORMULA
a(n+1) = b(n+1)*a(n)^2 + a(n), with a(1) = 4, where b(n) is defined in A376048.
EXAMPLE
The first few values of S(n) are 0/1, 3/4, 19/20, 1619/1620, 2626019/2626020, 34479907828019/34479907828020, ...
CROSSREFS
KEYWORD
nonn,base,frac
AUTHOR
N. J. A. Sloane, Sep 13 2024.
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Oct 18 2024
STATUS
approved