Number of 4 X 4 0..n arrays with row and column sums equal.

Terms

a(0) =1a(1) =140a(2) =5673a(3) =89520a(4) =790425a(5) =4756140a(6) =21841937a(7) =82112704a(8) =264639729a(9) =754898668a(10) =1950230969a(11) =4641494832a(12) =10309971465a(13) =21592075596a(14) =42980713761a(15) =81851507456a(16) =149924818657a(17) =265300850124a(18) =455235310153a(19) =759857498672