Rare numbers: Difference between revisions
Added Lua
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<syntaxhighlight lang="langur">val .reverse = f toNumber join reverse split .n</syntaxhighlight>
=={{header|Lua}}==
{{Trans|Phix|niave version, via FreeBASIC and Algol 68}}
<syntaxhighlight lang="lua">
do -- find the first five rare numbers
local function revn ( na )
local n, r = na, 0
while n > 0 do
r = r * 10 r = r + ( n % 10 )
n = math.floor( n / 10 )
end
return r
end -- revn
local nd, count, lim, n = 2, 0, 90, 20
local oddNd = nd % 2 == 1
while true do
n = n + 1
local r = revn( n )
if r < n then
local s, d = n + r, n - r
local tryThis = false
if oddNd
then tryThis = d % 1089 == 0
else tryThis = s % 121 == 0
end
if tryThis then
local rootS = math.sqrt( s )
if rootS == math.floor(rootS )
then
local rootD = math.sqrt( d )
if rootD == math.floor( rootD )
then
count = count + 1
io.write( count, ": ", n, "\n" )
if count >= 5 then os.exit() end
end
end
end
if n == lim
then
lim = lim * 10
nd = nd + 1
oddNd = not oddNd
n = math.floor( lim / 9 ) * 2
end
end
end
end
</syntaxhighlight>
{{out}}
<pre>
1: 65
2: 621770
3: 281089082
4: 2022652202
5: 2042832002
</pre>
=={{header|Mathematica}}/{{header|Wolfram Language}}==
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