[alexandria-devel] Subfactorial is wrong starting from 11

[Sergey Dymchenko]

Will this be fixed in the library repository?

On Sun, Jan 23, 2011 at 11:07 PM, Mason Smith <masonium at gmail.com> wrote:
> Here is a correct, linear-time implementation of subfactorial:
> (defun subfactorial (n)
>   "Subfactorial of the non-negative integer N."
>   (check-type n (integer 0))
>   (if (zerop n)
>       1
>     (do ((x 1 (1+ x))
> (a 0 (* x (+ a b)))
> (b 1 a))
> ((= n x) a))))
> and the corresponding test
> (deftest subfactorial.1
>     (mapcar #'subfactorial (iota 22))
>   (1 0 1 2 9 44 265 1854 14833 133496 1334961
>    14684570 176214841 2290792932 32071101049
>    481066515734 7697064251745 130850092279664
>    2355301661033953 44750731559645106
>    895014631192902121 18795307255050944540)).
>
>
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