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A140793 Smallest prime which is the concatenation of 2 or more consecutive numbers starting with n. 0
23, 345678910111213141516171819, 4567, 567891011121314151617, 67, 78910111213, 89 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Comment from Ray G. Opao, Sep 30 2008: a(9) is the following number:

91011121314151617181920212223242526272829303132333435363738394041424

34445464748495051525354555657585960616263646566676869707172737475767

77879808182838485868788899091929394959697989910010110210310410510610

71081091101111121131141151161171181191201211221231241251261271281291

30131132133134135136137138139140141142143144145146147148149150151152

15315415515615715815916016116216316416516616716816917017117217317417

5176177178179180181182183184185186187.

LINKS

Table of n, a(n) for n=2..8.

MATHEMATICA

f[n_] := Block[{c = n, k = n + 1}, While[c = 10^IntegerLength[k] c + k; p = c; !PrimeQ[c], k++]; c]; Table[f[n], {n, 2, 8}] (* Robert G. Wilson v, Jun 24 2012 *)

pr[n_]:=Module[{k=1}, While[!PrimeQ[FromDigits[Flatten[IntegerDigits/@Range[n, n+k]]]], k++]; FromDigits[Flatten[IntegerDigits/@Range[n, n+k]]]]; Array[pr, 8, 2] (* Harvey P. Dale, Mar 14 2014 *)

CROSSREFS

Sequence in context: A030464 A180731 A053558 * A023923 A267334 A202184

Adjacent sequences:  A140790 A140791 A140792 * A140794 A140795 A140796

KEYWORD

nonn,base

AUTHOR

Lekraj Beedassy, Jul 15 2008

STATUS

approved

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Last modified July 21 17:20 EDT 2019. Contains 325198 sequences. (Running on oeis4.)