Number of symmetric nonnegative integer 9 X 9 matrices with sum of elements equal to 4*n, under action of dihedral group D_4.

A054549

Number of symmetric nonnegative integer 9 X 9 matrices with sum of elements equal to 4*n, under action of dihedral group D_4.

Terms

    a(0) =1a(1) =9a(2) =51a(3) =219a(4) =786a(5) =2466a(6) =6974a(7) =18126a(8) =43929a(9) =100321a(10) =217683a(11) =451707a(12) =901128a(13) =1735752a(14) =3239928a(15) =5878328a(16) =10393902a(17) =17950878a(18) =30340682a(19) =50273658a(20) =81787476a(21) =130811124a(22) =205935756a(23) =319456044a(24) =488764246a(25) =738197766a(26) =1101468114a(27) =1624826306a(28) =2371158504a(29) =3425244456

External references