A156435 - OEIS

A156435

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

%I #4 Dec 18 2015 18:17:16

%S 1,2,2,7,13,110,440,7010,34814,709332,4108632,100368324,667960824,

%T 18944759304,142719383676,4596517872930,38710991748930,

%U 1392671800456580,12976446818207108,514918876680042334,5262123025959154234

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Feb 09 2009