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 two or three distinct values for every i<=n and j<=n.
A211689
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 two or three distinct values for every i<=n and j<=n.
Terms
- a(0) =80a(1) =216a(2) =498a(3) =1064a(4) =2200a(5) =4448a(6) =8844a(7) =17552a(8) =34384a(9) =67836a(10) =132308a(11) =260904a(12) =509178a(13) =1006144a(14) =1969566a(15) =3904484a(16) =7675178a(17) =15271538a(18) =30158642a(19) =60234204a(20) =119509036a(21) =239563440a(22) =477465048a(23) =960417468a(24) =1922353398a(25) =3879214910a(26) =7795367130
External references
- oeis: A211689