A202246 Number of zero-sum -2..2 arrays of n elements with adjacent element differences also in -2..2

1, 3, 9, 31, 107, 387, 1415, 5231, 19477, 72933, 274339, 1035807, 3923229, 14900005, 56721943, 216377047, 826917803, 3165318823, 12133973901, 46575395693, 178988128029, 688588254425, 2651686966607, 10220607799703, 39426825300181

Offset

1,2

Comments

Column 2 of A202252

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

Some solutions for n=10
..0....2....1...-1...-2....2....0....0...-1....2....1...-1....0....2....1....1
..1....0....0....1....0....0....0...-1....1....2...-1...-1...-1....0...-1....0
..2....0....0...-1...-1...-1....1...-2....1....2....1....1...-1....2...-1...-1
..1...-2...-2....1....0....0...-1....0....0....0....0....1...-1....2....1...-2
..1....0...-2....1....0....2...-2....0...-1...-1...-2....0....1....1...-1....0
..0....0....0...-1....2....0....0....1....0...-2....0...-1...-1...-1....0....0
.-1....0....2...-1....1...-2....0....0...-1...-2....2....1....0....0....0....2
.-2...-2....1....0....1...-1....0....1....1...-2....0....1....0...-2....0....2
.-2....0...-1....1....0....1....0....0....1....0...-1....0....2...-2....0....0
..0....2....1....0...-1...-1....2....1...-1....1....0...-1....1...-2....1...-2

Crossrefs

Sequence in context: A148964 A148965 A130620 * A225340 A148966 A279971

Adjacent sequences: A202243 A202244 A202245 * A202247 A202248 A202249

Keyword

nonn

Author

R. H. Hardin Dec 14 2011

Status

approved