10DEFFNS="PRIMES" 20MODE7 30VDU23;8202;0;0;0; 40PRINTCHR$132;CHR$157;CHR$131;CHR$14 1;"Prime Numbers " 50PRINTCHR$132;CHR$157;CHR$131;CHR$14 1;"Prime Numbers " 60PRINTTAB(10,23);CHR$131;"by Andrew Medworth" 70VDU28,0,21,39,3 80PRINTCHR$130;"This prints all terms in the sequence" 90PRINTCHR$130;"x^2+x+41 and marks th em blue if they" 100PRINTCHR$130;"are prime, leaving th em white if not." 101PRINTCHR$131;"Other sequences to tr y are n^2+n+17" 102PRINTCHR$131;"and 2(n^2)+29. Just c hange line 180." 110PRINT''CHR$129;"Press SPACE to star t." 120 130REPEAT UNTIL GET=32 140CLS 150: 160VDU7 170n=1 180t%=n^2+n+41 190IF FNIsPrime(t%)=TRUE THEN PRINT" T erm ";n;" is ";t% ELSE PRINT" Term ";n;" is ";t% 200n=n+1:GOTO 180 210: 220DEFFNIsPrime(N%):LOCAL N,D%,K%,F%:I F(N%MOD2)=0 OR (N%MOD3)=0:=FALSE 230IFN%>42 AND N%<1602:N=(SQR(4*N%-163 )-1)/2:IFN=INTN:=TRUE 240D%=1:J%=4:REPEAT D%=D%+J%:J%=6-J%:F %=(N% MOD D%)=0:UNTILF% OR D%>=SQR(N%):= NOT(F% AND D%<=SQR(N%))