login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128296 a(n) = denominator of b(n): b(1)=1; b(n+1) = b(n) * [b(1);b(2),...,b(n)], where [...] is a continued fraction of rational terms. 2
1, 1, 1, 3, 99, 1917729, 695291630330558547, 2868367896364283363830544991834226772439236224131 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(9) and a(10) have 129 and 341 digits, respectively and are too large to include here. - R. J. Mathar, Oct 08 2007

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

a(5) = the denominator of b(5). b(5) = (10/3) * (1 +1/(1 +1/(2 +3/10))) = 560/99.

MAPLE

L2cfrac := proc(L) local a, i; a := op(-1, L) ; for i from 2 to nops(L) do a := op(-i, L)+1/a ; od: RETURN(a) ; end: A128296 := proc() local b, n, bnxt; b := [1] ; for n from 2 to 10 do bnxt := op(-1, b)*L2cfrac(b) ; b := [op(b), bnxt] ; od: [seq( denom(b[i]), i=1..nops(b))] ; end: A128296() ; # R. J. Mathar, Oct 08 2007

CROSSREFS

Cf. A128295.

Sequence in context: A180350 A293952 A303826 * A037114 A336437 A069457

Adjacent sequences:  A128293 A128294 A128295 * A128297 A128298 A128299

KEYWORD

frac,nonn

AUTHOR

Leroy Quet, Feb 25 2007

EXTENSIONS

More terms from R. J. Mathar, Oct 08 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 8 14:22 EDT 2022. Contains 356009 sequences. (Running on oeis4.)