A274008 Number of length-n ternary sequences where the sum of each block differs by at most 1 from every other block of the same length.

1, 3, 7, 15, 27, 47, 71, 107, 151, 207, 271, 355, 447, 563, 691, 835, 995, 1187, 1391, 1631, 1887, 2167, 2467, 2811, 3171, 3571, 3995, 4455, 4939, 5479, 6035, 6651, 7299, 7987, 8707, 9475, 10267, 11131, 12031, 12979, 13959, 15019, 16103, 17271, 18479, 19735

Offset: 0

Author

Jeffrey Shallit, Jun 06 2016

Keywords

• nonn

Examples

			For n = 2 the only strings omitted are 02 and 20.
		

Crossrefs

Cf. A005598, which is the analogous sequence where "ternary" is replaced by "binary".

Cf. A274005, which is the analogous sequence where "ternary" is replaced by "binary" and "1" is replaced by "2".

Formula

a(n) = 2*A005598(n) - 1. - Rémy Sigrist, Oct 11 2022

Extensions

More terms from Rémy Sigrist, Oct 11 2022