A127815 a(n) = denominator of b(n), where b(1) = 2, b(n) = b(n-1) - 1/b(n-1).

1, 2, 6, 30, 330, 257070, 128005692870, 23279147893155496537470, 388475314992168993748220639081347493631827670, 102339769648127358726761918460732576814168548432921287355299929744910591862606847215978930

Offset: 1

Author

Leroy Quet, Jan 30 2007

Keywords

• easy
• frac
• nonn

Examples

			A127814/A127815 = 2, 3/2, 5/6, -11/30, 779/330, 497941/257070, 181860254581/128005692870, ...
		

Crossrefs

Cf. A127814.

Programs

Mathematica

f[l_List] := Append[l, l[[ -1]] - 1/l[[ -1]]];Denominator[Nest[f, {2}, 10]] (* Ray Chandler, Feb 07 2007 *)

Formula

For n >= 2, a(n) = a(n-1)*A127814(n-1).

Extensions

Extended by Ray Chandler, Feb 07 2007