A114794 Smallest prime beginning with the concatenation of first n primes.

2, 23, 2351, 2357, 2357119, 2357111357, 23571113171, 23571113171939, 2357111317192343, 23571113171923297, 2357111317192329319, 235711131719232931373, 235711131719232931374149

Offset

1,1

Links

Table of n, a(n) for n=1..13.

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 A379426

Adjacent sequences: A114791 A114792 A114793 * A114795 A114796 A114797

Keyword

base,nonn

Author

Amarnath Murthy, Nov 19 2005

Extensions

More terms from R. J. Mathar, Jan 25 2008

Status

approved