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A113890 Smallest prime of the form: all eights followed by prime(n). a(n)> prime(n). 0 if no such prime exists. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 12 23:52 EDT 2022. Contains 356077 sequences. (Running on oeis4.)