Fourth power of lower triangular matrix of A056857 (successive equalities in set partitions of n).

Terms

a(0) =1a(1) =4a(2) =1a(3) =20a(4) =8a(5) =1a(6) =116a(7) =60a(8) =12a(9) =1a(10) =756a(11) =464a(12) =120a(13) =16a(14) =1a(15) =5428a(16) =3780a(17) =1160a(18) =200a(19) =20a(20) =1a(21) =42356a(22) =32568a(23) =11340a(24) =2320a(25) =300a(26) =24a(27) =1a(28) =355636a(29) =296492