Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 4.

A156435

Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 4.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =7a(4) =13a(5) =110a(6) =440a(7) =7010a(8) =34814a(9) =709332a(10) =4108632a(11) =100368324a(12) =667960824a(13) =18944759304a(14) =142719383676

External references