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A114794
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Smallest prime beginning with the concatenation of first n primes.
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1
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2, 23, 2351, 2357, 2357119, 2357111357, 23571113171, 23571113171939, 2357111317192343, 23571113171923297, 2357111317192329319, 235711131719232931373, 235711131719232931374149
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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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a(5) = 2357119 as 2357111,2357113,2357117 are composite.
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MAPLE
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A055642 := proc(n) max(1, ilog10(n)+1) ; end: glue := proc(a, b) a*10^A055642(b)+b ; end: A019518 := proc(n) local a, j, p ; a := 2; for j from 2 to n do p := ithprime(j) ; a := glue(a, p) ; od: RETURN(a) ; end: A114794 := proc(n) local b, j ; b := A019518(n) ; if isprime(b) then RETURN(b) ; else for j from 1 do if isprime(glue(b, j)) then RETURN( glue(b, j) ) ; fi ; od: fi ; end: seq(A114794(n), n=1..20) ; # R. J. Mathar, Jan 25 2008
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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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