Ulam spiral (for primes): Difference between revisions
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2 IF p=n THEN LET pr=pr+1: LET kx=(255-xx AND k<3)+(xx AND k>2): LET ky=(175-yy AND (k=1 OR k=3)+(yy AND (k=2 OR k=4))): PLOT kx,ky: PRINT #0;AT 0,0;n;" pr";pr
3 RETURN
10 CLS : PRINT "
12 INPUT "square size= LxL"'"l: ";l: IF l<>INT l OR l<1 OR l>176 THEN GO TO 12
13 LET max=l*l: PRINT ''l;"x";l;"=";max;" positive integers"
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