Fourth column of triangle A112500.

Terms

a(0) =1a(1) =20a(2) =225a(3) =1882a(4) =13070a(5) =79872a(6) =444902a(7) =2311828a(8) =11388999a(9) =53820068a(10) =246112783a(11) =1096379070a(12) =4782801180a(13) =20515294320a(14) =86808499020a(15) =363304109640