Number of -1..1 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 one, two or three distinct values for every i<=n and j<=n.
A211478
Number of -1..1 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 one, two or three distinct values for every i<=n and j<=n.
Terms
- a(0) =9a(1) =23a(2) =59a(3) =145a(4) =351a(5) =835a(6) =1971a(7) =4625a(8) =10831a(9) =25349a(10) =59387a(11) =139365a(12) =327791a(13) =772867a(14) =1826897a(15) =4329065a(16) =10282271a(17) =24474781a(18) =58370829a(19) =139453231a(20) =333678255a(21) =799483191a(22) =1917764183a(23) =4604847317a(24) =11066414301a(25) =26614313429a(26) =64046049399
External references
- oeis: A211478