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A335271
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Full autoinsertable primes are such primes that remain prime after all the possible internal autoinsertions, one at a time.
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1
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131, 173, 179, 191, 197, 283, 293, 367, 383, 401, 547, 587, 641, 701, 709, 757, 797, 827, 12197, 12289, 53881, 54779, 68927, 37898818253
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OFFSET
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1,1
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COMMENTS
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Supposed to have only a finite quantity of terms. If the prime has K digits all the possible internal autoinsertions are K-1.
If it exists, the next term is > 2^32.
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LINKS
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EXAMPLE
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The prime 131 can be inserted into itself in two positions: 1'131'31, 13'131'1. Both are primes.
The prime 68927 can be inserted into itself in four positions: 6'68927'8927, 68'68927'927, 689'68927'27, 6892'68927'7. All the four are primes.
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PROG
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(PARI) forprime(p=11, 10^8, my(v=digits(p), d=#v, f=1); for(i=1, d-1, my(t=concat(concat(v[1..i], v), v[i+1..d]), q=fromdigits(t)); if(!isprime(q), f=0; break)); if(f, print1(p, ", "))) \\ Hugo Pfoertner, May 30 2020
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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