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a(n) is least N > 1 congruent to -1,0, or 1 mod i for all i=1,...,n.
5

%I #41 May 18 2024 11:34:59

%S 2,2,2,3,4,5,29,41,55,71,791,791,1079,1079,1079,30239,246960,246960,

%T 636481,636481,1360800,2162161,2162161,2162161,39412801,39412801,

%U 107881201,107881201,3625549201,3625549201,3625549201,170918748000,170918748000,170918748000,170918748000,170918748000,2355997644001

%N a(n) is least N > 1 congruent to -1,0, or 1 mod i for all i=1,...,n.

%H Don Reble, <a href="/A056697/b056697.txt">Table of n, a(n) for n = 1..156</a>

%H Don Reble, <a href="/A056697/a056697.txt">Notes on the computation of A056697</a>.

%F Since n! - 1 == -1 (mod i) for all i = 1..n, a(n) <= n! - 1 for n > 2. - _N. J. A. Sloane_, Dec 30 2012

%e a(9) = 55 because 55 gives remainder -1 when divided by 2,4,7 and 8, gives remainder 0 when divided by (1 and) 5, and gives remainder 1 when divided by 3,6 and 9. All smaller integers greater than 1 give remainders other than -1, 0, or 1 for at least one of 5,6,7,8, or 9.

%Y One version of an inverse function to A187824. For another version see A220890. See also A220891. - _N. J. A. Sloane_, Dec 30 2012

%K nonn

%O 1,1

%A _Ted Alper_, Aug 10 2000

%E More terms from _Don Reble_, Dec 30 2012