Ludic numbers: Difference between revisions

=={{header|Lua}}==

<lang Lua>-- Return table of ludic numbers below limit

function ludics (limit)

local ludList, numList, index = {1}, {}

for n = 2, limit do table.insert(numList, n) end

while #numList > 0 do

index = numList[1]

table.insert(ludList, index)

for key = #numList, 1, -1 do

if key % index == 1 then table.remove(numList, key) end

end

end

return ludList

end

-- Return true if n is found in t or false otherwise

function foundIn (t, n)

for k, v in pairs(t) do

if v == n then return true end

end

return false

end

-- Display msg followed by all values in t

function show (msg, t)

io.write(msg)

for _, v in pairs(t) do io.write(" " .. v) end

print("\n")

end

-- Main procedure

local first25, under1k, inRange, tripList, triplets = {}, 0, {}, {}, {}

for k, v in pairs(ludics(30000)) do

if k < 25 then table.insert(first25, v) end

if v <= 1000 then under1k = under1k + 1 end

if k >= 2000 and k <= 2005 then table.insert(inRange, v) end

if v < 250 then table.insert(tripList, v) end

end

for _, x in pairs(tripList) do

if foundIn(tripList, x + 2) and foundIn(tripList, x + 6) then

table.insert(triplets, "\n{" .. x .. "," .. x+2 .. "," .. x+6 .. "}")

end

end

show("First 25:", first25)

print(under1k .. " are less than or equal to 1000\n")

show("2000th to 2005th:", inRange)

show("Triplets:", triplets)</lang>

{{out}}

<pre>First 25: 1 2 3 5 7 11 13 17 23 25 29 37 41 43 47 53 61 67 71 77 83 89 91 97

142 are less than or equal to 1000

2000th to 2005th: 21475 21481 21487 21493 21503 21511

Triplets:

{1,3,7}

{5,7,11}

{11,13,17}

{23,25,29}

{41,43,47}

{173,175,179}

{221,223,227}

{233,235,239}</pre>