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, 2, 4, 28, 924, 1301916, 2192719475100, 6877436791939871875340700, 63662093585928604457207470763864412072759112460700, 5654964592175973912056572385731364781410655247698710272187424640218106099883341821471858427090700700

Offset

0,4

Links

Table of n, a(n) for n=0..11.

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

Cf. A064845, A064846, A126579.

Sequence in context: A292184 A248872 A329102 * A329063 A124687 A267122

Adjacent sequences: A126577 A126578 A126579 * A126581 A126582 A126583

Keyword

easy,frac,nonn

Author

Leroy Quet, Dec 28 2006

Extensions

Extended by Ray Chandler, Dec 29 2006

Status

approved