The leading partial quotients [3; 7, 15, 1, 292, ...] are tabulated rather than derived: a double cannot supply them past the tenth, so asking for more than fifteen is refused instead of answered with noise. The early convergents are the classical 22/7, 333/106 and 355/113.
Examples
Conti(4)
#> $estimate
#> [1] 3.141593
#>
#> $terms
#> [1] 3 7 15 1
#>
#> $convergents
#> hs ks
#> [1,] 3 1
#> [2,] 22 7
#> [3,] 333 106
#> [4,] 355 113
#>
#> $numerator
#> [1] 355
#>
#> $denominator
#> [1] 113
#>
#> $error
#> [1] 2.667642e-07
#>
#> $n
#> [1] 4
#>
#> $method
#> [1] "continued fraction convergents of pi"
#>
