A113890 - OEIS

A113890

Smallest prime of the form: all eights followed by prime(n). a(n)> prime(n). 0 if no such prime exists.

0, 83, 0, 887, 811, 88813, 88817, 8819, 823, 829, 8831, 8837, 88888841, 88843, 88888888888888888888888888888847, 853, 859, 8861, 8867, 888871, 88873, 88888879, 883, 88888888888889, 88897, 8101, 888103, 8888107, 888109

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OFFSET

1,2

COMMENTS

Prime(n) is all zeros followed by prime(n). This is all eights followed by prime(n). Conjecture: a(n) is nonzero if n > 3.

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

a(4) = 887, as 87 is composite, prime(4) = 7.

MAPLE

cat2 := proc(a, b) a*10^(max(1, ilog10(b)+1))+b ; end: A002282 := proc(n) 8*(10^n-1)/9 ; end: A113890 := proc(n) local p, a, n8 ; p := ithprime(n) ; for n8 from 1 to 120 do a := cat2(A002282(n8), p) ; if isprime(a) then return(a) ; fi ; od: RETURN(0) ; end: seq(A113890(n), n=1..35) ; # R. J. Mathar, Jan 31 2008

CROSSREFS

Cf. A113884, A114785, A113886, A113887, A085074, A114789.

Sequence in context: A235982 A116296 A324674 * A051327 A272637 A317915

Adjacent sequences: A113887 A113888 A113889 * A113891 A113892 A113893

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Nov 18 2005

EXTENSIONS

More terms from R. J. Mathar, Jan 31 2008

STATUS

approved