A056697 a(n) is least N > 1 congruent to -1,0, or 1 mod i for all i=1,...,n.

2, 2, 2, 3, 4, 5, 29, 41, 55, 71, 791, 791, 1079, 1079, 1079, 30239, 246960, 246960, 636481, 636481, 1360800, 2162161, 2162161, 2162161, 39412801, 39412801, 107881201, 107881201, 3625549201, 3625549201, 3625549201, 170918748000, 170918748000, 170918748000, 170918748000, 170918748000, 2355997644001

Offset: 1

Author

Ted Alper, Aug 10 2000

Keywords

• nonn

Examples

			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.
		

Links

• Don Reble, Table of n, a(n) for n = 1..156
• Don Reble, Notes on the computation of A056697.

Crossrefs

One version of an inverse function to A187824. For another version see A220890. See also A220891. - N. J. A. Sloane, Dec 30 2012

Formula

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

Extensions

More terms from Don Reble, Dec 30 2012