Number of set partitions of {1, 2, ..., 2*n} with sizes in {[n, n], [2n]}.
A260878
Number of set partitions of {1, 2, ..., 2*n} with sizes in {[n, n], [2n]}.
Terms
- a(0) =2a(1) =2a(2) =4a(3) =11a(4) =36a(5) =127a(6) =463a(7) =1717a(8) =6436a(9) =24311a(10) =92379a(11) =352717a(12) =1352079a(13) =5200301a(14) =20058301a(15) =77558761a(16) =300540196a(17) =1166803111a(18) =4537567651a(19) =17672631901a(20) =68923264411a(21) =269128937221
External references
- oeis: A260878