Weird numbers: Difference between revisions

70 836 4030 5830 7192 7912 9272 10430 10570 10792 10990 11410 11690 12110 12530 12670 13370 13510 13790 13930 14770 15610 15890 16030 16310</pre>

=={{header|Nim}}==

{{trans|Go}}

<lang Nim>import algorithm, math, strutils

func divisors(n: int): seq[int] =

var smallDivs = @[1]

for i in 2..sqrt(n.toFloat).int:

if n mod i == 0:

let j = n div i

smallDivs.add i

if i != j: result.add j

result.add reversed(smallDivs)

func abundant(n: int; divs: seq[int]): bool {.inline.}=

sum(divs) > n

func semiperfect(n: int; divs: seq[int]): bool =

if divs.len > 0:

let h = divs[0]

let t = divs[1..^1]

result = if n < h: semiperfect(n, t)

else: n == h or semiperfect(n - h, t) or semiperfect(n, t)

func sieve(limit: int): seq[bool] =

# False denotes abundant and not semi-perfect.

# Only interested in even numbers >= 2.

result.setLen(limit)

for i in countup(2, limit - 1, 2):

if result[i]: continue

let divs = divisors(i)

if not abundant(i, divs):

result[i] = true

elif semiperfect(i, divs):

for j in countup(i, limit - 1, i):

result[j] = true

const Max = 25

let w = sieve(17_000)

var list: seq[int]

echo "The first 25 weird numbers are:"

var n = 2

while list.len != Max:

if not w[n]: list.add n

inc n, 2

echo list.join(" ")</lang>

{{out}}

<pre>The first 25 weird numbers are: