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A052077 Smallest prime formed by concatenating n consecutive increasing numbers, or 0 if no such prime exists. 7

%I

%S 2,23,0,4567,1516171819,0,78910111213,23456789,0,45678910111213,

%T 129130131132133134135136137138139,0,567891011121314151617,

%U 5051525354555657585960616263,0,128129130131132133134135136137138139140141142143

%N Smallest prime formed by concatenating n consecutive increasing numbers, or 0 if no such prime exists.

%C Starting numbers in concatenations are given by A052079.

%H Paolo P. Lava, <a href="/A052077/b052077.txt">Table of n, a(n) for n = 1..43</a>

%H C. Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_078.htm">Prime Puzzle 78</a>

%t f[n_] := If[Mod[n, 3] == 0, 0, Block[{k = 1}, While[d = FromDigits@ Flatten@ IntegerDigits[ Range[k, k + n - 1]]; !PrimeQ@ d, k++]; d]]; Array[f, 16] (* _Robert G. Wilson v_, Jun 29 2012 *)

%Y Cf. A052078, A052079, A052080, A030997.

%K nonn,base,nice

%O 1,1

%A _Patrick De Geest_, Jan 15 2000

%E Terms a(7)-a(15) are calculated by _Carlos Rivera_ and _Felice Russo_

%E a(16) from _Max Alekseyev_, Jan 31 2010

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Last modified August 14 01:55 EDT 2020. Contains 336476 sequences. (Running on oeis4.)