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A128192
a(n) = denominator of b(n), where b(1)=1, b(n+1) = sum{k=1 to n} {b(n+1-k)/k} ({x} is the fractional part of x).
1
1, 1, 2, 6, 3, 60, 360, 2520, 1680, 15120, 2800, 831600, 9979200, 9266400, 165110400, 27243216000, 27243216000, 102918816000, 793945152000, 355537728000, 150849578880000, 22174888095360000, 3049047113112000, 43155743754816000
OFFSET
1,3
MATHEMATICA
f[l_List] := Block[{n = Length[l]}, Append[l, Sum[ FractionalPart[l[[n + 1 - k]]/k], {k, n}]]]; Denominator[Nest[f, {1}, 23]] (* Ray Chandler, Feb 26 2007 *)
CROSSREFS
Cf. A128191.
Sequence in context: A206429 A101819 A177761 * A354375 A077750 A332253
KEYWORD
frac,nonn
AUTHOR
Leroy Quet, Feb 17 2007
EXTENSIONS
Extended by Ray Chandler, Feb 26 2007
STATUS
approved