Number of (n+1) X (n+1) -5..5 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.

A211329

Number of (n+1) X (n+1) -5..5 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.

Terms

    a(0) =15a(1) =19a(2) =25a(3) =35a(4) =51a(5) =77a(6) =119a(7) =187a(8) =297a(9) =475a(10) =763a(11) =1229a(12) =1983a(13) =3203a(14) =5177a(15) =8371a(16) =13539a(17) =21901a(18) =35431a(19) =57323a(20) =92745a(21) =150059a(22) =242795a(23) =392845a(24) =635631a(25) =1028467a(26) =1664089a(27) =2692547a(28) =4356627a(29) =7049165

External references