Number of -4..4 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.
A211690
Number of -4..4 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) =81a(1) =233a(2) =579a(3) =1373a(4) =3147a(5) =7161a(6) =16061a(7) =36193a(8) =81085a(9) =183171a(10) =413329a(11) =940933a(12) =2145151a(13) =4930245a(14) =11361373a(15) =26362361a(16) =61352875a(17) =143585559a(18) =336993507a(19) =794383691a(20) =1877216725a(21) =4450883361a(22) =10574607261a(23) =25186420645a(24) =60085979449
External references
- oeis: A211690