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A080830
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Primes that terminate at 68,34,17 in the 3x-1 problem: Repeat, if x is even divide by 2 else multiply by 3 and subtract 1, until 17 is reached.
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0
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17, 23, 31, 37, 41, 61, 67, 73, 83, 109, 131, 163, 179, 197, 229, 233, 239, 257, 263, 277, 293, 311, 313, 331, 337, 349, 389, 439, 443, 449, 457, 467, 491, 521, 523, 557, 577, 587, 599, 641, 659, 661, 673, 677, 701, 739, 743, 757, 761, 769, 773, 787, 829, 877
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OFFSET
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1,1
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LINKS
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PROG
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(PARI) px3nm1(n, p) = { forprime(x=2, n, p1 = x; while(p1>1, if(p1%2==0, p1/=2, p1 = p1*p-1; ); if(p1 == 5 || p1==17, break); ); if(p1 == 17, print1(x" ")) ) }
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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