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A123216
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Concatenated index primes. Primes whose indices are the concatenation of the consecutive integers.
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0
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2, 37, 677, 10061, 132241, 1632899, 19394489, 224284387, 2543568463, 313945524931, 37301821050191, 4317408693770701, 490210240132738471
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OFFSET
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1,1
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COMMENTS
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a(10) was taken from a file of all primes < 1 trillion. The next term, prime(1234567891011) ~ 37301821238347 is exact in the first 7 places. This and larger indices can be computed with an exponential bisection routine given in the link.
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LINKS
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FORMULA
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EXAMPLE
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The concatenation of the first three integers is 123. Prime(123) = 677, the 3rd term.
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MATHEMATICA
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PROG
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(PARI) g(n) = st=""; for(x=1, n, st=concat(st, Str(x)); print1(prime(eval(st))", "))
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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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