Triangle, read by rows, where T(n,k) = C( n*(n+1)/2 + n-k + 1, n-k), for n>=k>=0.

Terms

a(0) =1a(1) =3a(2) =1a(3) =15a(4) =5a(5) =1a(6) =120a(7) =36a(8) =8a(9) =1a(10) =1365a(11) =364a(12) =78a(13) =12a(14) =1a(15) =20349a(16) =4845a(17) =969a(18) =153a(19) =17a(20) =1a(21) =376740a(22) =80730a(23) =14950a(24) =2300a(25) =276a(26) =23a(27) =1a(28) =8347680a(29) =1623160