Number of positive integer square matrices with entries summing to n and equal row and column sums.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =3a(7) =1a(8) =4a(9) =2a(10) =5a(11) =1a(12) =12a(13) =1a(14) =7a(15) =22a(16) =9a(17) =1a(18) =64a(19) =1a(20) =34a(21) =121a(22) =11a(23) =1a(24) =525a(25) =2a(26) =13a(27) =407a(28) =2022a(29) =1