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A239747
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Super-prime leaders: right-truncatable primes p with property that appending any single decimal digit to p does not produce a prime.
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3
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53, 317, 599, 797, 2393, 3793, 3797, 7331, 23333, 23339, 31193, 31379, 37397, 73331, 373393, 593993, 719333, 739397, 739399, 2399333, 7393931, 7393933, 23399339, 29399999, 37337999, 59393339, 73939133
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OFFSET
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1,1
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COMMENTS
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The name "super-prime leaders" is not due to the author.
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REFERENCES
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Joe Roberts, Lure of the Integers, The Mathematical Association of America, 1992, p. 292.
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LINKS
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FORMULA
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EXAMPLE
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2393 belongs to this sequence because 2393, 239, 23 and 2 are all prime; 10*2393 + k, for k = 0 to 9, are all composite.
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PROG
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(PARI) f=1; for(n=2, 73939133, v=n; t=1; while(isprime(n), if(!Mod(f, n^2)==0, t=t*n); c=n; n=(c-lift(Mod(c, 10)))/10); if(n==0, f=f*t); n=v); s=Set(factor(f)[, 1]); for(k=1, #s, p=s[k]; if(!Mod(f, p^2)==0, print1(p, ", ")));
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CROSSREFS
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KEYWORD
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nonn,base,fini,full
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AUTHOR
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STATUS
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approved
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