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Quadrat special primes: Difference between revisions
Added solution for Action!
(→{{header|ALGOL 68}}: Use ALGOL 68-primes) |
(Added solution for Action!) |
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where the successor of q is the least prime, p, such that p - q is a perfect square.
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=={{header|Action!}}==
{{libheader|Action! Sieve of Eratosthenes}}
<lang Action!>INCLUDE "H6:SIEVE.ACT"
DEFINE MAX="15999"
DEFINE MAXSQUARES="126"
BYTE ARRAY primes(MAX+1)
INT ARRAY squares(MAXSQUARES)
PROC CalcSquares()
INT i
FOR i=1 TO MAXSQUARES
DO
squares(i-1)=i*i
OD
RETURN
INT FUNC FindNextQuadraticPrime(INT x)
INT i,next
FOR i=0 TO MAXSQUARES-1
DO
next=x+squares(i)
IF next>MAX THEN
RETURN (-1)
FI
IF primes(next) THEN
RETURN (next)
FI
OD
RETURN (-1)
PROC Main()
INT p=[2]
Put(125) PutE() ;clear the screen
Sieve(primes,MAX+1)
CalcSquares()
WHILE p>0
DO
PrintI(p) Put(32)
p=FindNextQuadraticPrime(p)
OD
RETURN</lang>
{{out}}
[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Quadrat_Special_Primes.png Screenshot from Atari 8-bit computer]
<pre>
2 3 7 11 47 83 227 263 587 911 947 983 1019 1163 1307 1451 1487 1523 1559 2459
3359 4259 4583 5483 5519 5843 5879 6203 6779 7103 7247 7283 7607 7643 8219 8363
10667 11243 11279 11423 12323 12647 12791 13367 13691 14591 14627 14771 15671
</pre>
=={{header|ALGOL 68}}==
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