8 lines
328 B
Common Lisp
8 lines
328 B
Common Lisp
|
(loop for candidate from 2 below (expt 2 19)
|
||
|
|
for sum = (+ (/ candidate)
|
||
|
|
(loop for factor from 2 to (isqrt candidate)
|
||
|
|
when (zerop (mod candidate factor))
|
||
|
|
sum (+ (/ factor) (/ (floor candidate factor)))))
|
||
|
|
when (= sum 1)
|
||
|
|
collect candidate)
|