A211500 Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having two or three distinct values for every i<=n and j<=n

48, 130, 298, 660, 1384, 2890, 5850, 11930, 23806, 48056, 95422, 191866, 380806, 765090, 1521180, 3058882, 6098874, 12284898, 24573634, 49602712, 99555058, 201409462, 405573782, 822380214, 1661216936, 3375887170, 6839392998

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +13*a(n-2) -43*a(n-3) -67*a(n-4) +254*a(n-5) +171*a(n-6) -797*a(n-7) -213*a(n-8) +1427*a(n-9) +85*a(n-10) -1458*a(n-11) +60*a(n-12) +810*a(n-13) -58*a(n-14) -224*a(n-15) +12*a(n-16) +24*a(n-17)

Example

Some solutions for n=5
..0....0....3....0...-1....2...-2...-3...-1...-3....2...-3...-3...-1...-1....1
.-1....1...-1....1...-1....2...-3....1...-3....1...-2...-2....3....0...-1....0
.-2...-3....1....0....1....2...-2....1...-1...-3....2...-1....3...-1....3...-1
.-1....1...-1...-2....3....2...-1...-3....3....1...-2...-2....3....0...-1....0
..0....0...-1....0....1...-2....0....1...-1...-2....2...-1....3...-1....3...-1
.-1...-2...-1...-2....3....2....1...-3....2....1....0...-2...-3....0...-1...-2

Crossrefs

Sequence in context: A114444 A044299 A044680 * A295428 A118145 A260833

Adjacent sequences: A211497 A211498 A211499 * A211501 A211502 A211503

Keyword

nonn

Author

R. H. Hardin Apr 13 2012

Status

approved