Number of (n+1) X (n+1) -3..3 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.

A211322

Number of (n+1) X (n+1) -3..3 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.

Terms

    a(0) =11a(1) =15a(2) =21a(3) =31a(4) =47a(5) =73a(6) =115a(7) =183a(8) =293a(9) =471a(10) =759a(11) =1225a(12) =1979a(13) =3199a(14) =5173a(15) =8367a(16) =13535a(17) =21897a(18) =35427a(19) =57319a(20) =92741a(21) =150055a(22) =242791a(23) =392841a(24) =635627a(25) =1028463a(26) =1664085a(27) =2692543a(28) =4356623a(29) =7049161

External references