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

Terms

a(0) =1a(1) =2a(2) =1a(3) =6a(4) =4a(5) =1a(6) =22a(7) =18a(8) =6a(9) =1a(10) =94a(11) =88a(12) =36a(13) =8a(14) =1a(15) =454a(16) =470a(17) =220a(18) =60a(19) =10a(20) =1a(21) =2430a(22) =2724a(23) =1410a(24) =440a(25) =90a(26) =12a(27) =1a(28) =14214a(29) =17010