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A126580
a(n) = denominator of r_n, where r_0 =0, r_1 =1, r_{n+1} = the continued fraction (of rational terms) [r_0,r_1,r_2,r_3,...,r_n].
1
1, 1, 1, 2, 4, 28, 924, 1301916, 2192719475100, 6877436791939871875340700, 63662093585928604457207470763864412072759112460700, 5654964592175973912056572385731364781410655247698710272187424640218106099883341821471858427090700700
OFFSET
0,4
EXAMPLE
a(5) is the denominator of r_5 = r_0 +1/(r_1 +1/(r_2
+1/(r_3 + 1/r_4))) =
0 + 1/(1 +1/(1 +1/(1/2 +1/(3/4)))) = 17/28.
MATHEMATICA
f[l_List] := Append[l, FromContinuedFraction[l]]; Denominator@Nest[f, {0, 1}, 10] (* Ray Chandler, Dec 29 2006 *)
CROSSREFS
KEYWORD
easy,frac,nonn
AUTHOR
Leroy Quet, Dec 28 2006
EXTENSIONS
Extended by Ray Chandler, Dec 29 2006
STATUS
approved