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A114794 Smallest prime beginning with the concatenation of first n primes. 1
2, 23, 2351, 2357, 2357119, 2357111357, 23571113171, 23571113171939, 2357111317192343, 23571113171923297, 2357111317192329319, 235711131719232931373, 235711131719232931374149 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) >= A019518(n). - R. J. Mathar, Jan 25 2008
EXAMPLE
a(5) = 2357119 as 2357111,2357113,2357117 are composite.
MAPLE
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
CROSSREFS
Sequence in context: A083759 A240563 A067823 * A090509 A069151 A227529
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 19 2005
EXTENSIONS
More terms from R. J. Mathar, Jan 25 2008
STATUS
approved

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Last modified July 14 19:09 EDT 2024. Contains 374323 sequences. (Running on oeis4.)