RosettaCodeData/Task/Wieferich-primes/Run-BASIC/wieferich-primes.basic
2023-07-01 13:44:08 -04:00

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655 B
Text

print "Wieferich primes less than 5000: "
for i = 1 to 5000
if isWeiferich(i) then print i
next i
end
function isPrime(n)
if n < 2 then isPrime = 0 : goto [exit]
if n = 2 then isPrime = 1 : goto [exit]
if n mod 2 = 0 then isPrime = 0 : goto [exit]
isPrime = 1
for i = 3 to int(n^.5) step 2
if n mod i = 0 then isPrime = 0 : goto [exit]
next i
[exit]
end function
function isWeiferich(p)
if isPrime(p) = 0 then isWeiferich = 0 : goto [exit]
q = 1
p2 = p^2
while p > 1
q = (2*q) mod p2
p = p - 1
wend
if q = 1 then
isWeiferich = 1 : goto [exit]
else
isWeiferich = 0 : goto [exit]
end if
[exit]
end function