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 A020498 a(n) is the least number > a(n-1) such that a(1) through a(n) do not contain all residues modulo any prime. 4

%I

%S 1,3,7,9,13,19,21,27,31,33,37,43,49,51,57,63,69,73,79,87,91,97,99,103,

%T 111,117,121,129,133,139,141,147,153,157,159,163,169,177,183,187,189,

%U 199,201,211,213,217,231,241,243,247,253,261,267,271,273,279,283,289

%N a(n) is the least number > a(n-1) such that a(1) through a(n) do not contain all residues modulo any prime.

%C Conjecturally, a(n) is the smallest number such that n primes occur infinitely often among (x+a(1), ...,x+a(n)).

%D R. K. Guy's "Unsolved Problems in Number Theory" (2nd edition, Springer, 1994), Section A9.

%H David W. Wilson, <a href="/A020498/b020498.txt">Table of n, a(n) for n = 1..10000</a>

%Y Cf. A020497, A008407.

%K nonn

%O 1,2

%A _Robert G. Wilson v_ and _Christopher E. Thompson_

%E More terms from _David Wasserman_, Aug 17 2005

%E Old name has been interchanged with Wasserman's comment, as old name only a conjectural definition of the sequence. Edited by _Christopher J. Smyth_, May 12 2016

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Last modified January 23 10:50 EST 2020. Contains 331171 sequences. (Running on oeis4.)