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A064490
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Smallest prime with prime(n) decimal digits.
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4
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11, 101, 10007, 1000003, 10000000019, 1000000000039, 10000000000000061, 1000000000000000003, 10000000000000000000009, 10000000000000000000000000331, 1000000000000000000000000000057, 1000000000000000000000000000000000067, 10000000000000000000000000000000000000121
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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11 is the first prime with 2 decimal digits.
101 is the first prime with 3 decimal digits.
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MAPLE
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for n from 1 to 20 do p := ithprime(n): for i from 10^(p-1) to 10^p do if isprime(i) then printf(`%d, `, i); break; fi: od: od:
# second Maple program:
a:= n-> nextprime(10^(ithprime(n)-1)):
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MATHEMATICA
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Table[NextPrime[10^(n-1)], {n, Prime[Range[15]]}] (* Harvey P. Dale, Feb 06 2020 *)
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PROG
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(PARI) l(n)=ln=0; while(n, n=floor(n/10); ln++); return(ln);
a=0; for(n=1, 10^6, x=l(prime(n)); if(isprime(x), b=x; if(b>a, a=b; print(prime(n)))))
(PARI) { for (n=1, 75, p=prime(n); a=nextprime(10^(p - 1)); write("b064490.txt", n, " ", a) ) } \\ Harry J. Smith, Sep 16 2009
(Python)
from sympy import prime, nextprime, primepi
def a(n): return nextprime(10**(prime(n)-1))
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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