Number of set partitions of [n] into exactly four blocks where sizes of distinct blocks are coprime.
A280882
Number of set partitions of [n] into exactly four blocks where sizes of distinct blocks are coprime.
Terms
- a(0) =1a(1) =10a(2) =20a(3) =245a(4) =56a(5) =2100a(6) =2640a(7) =36795a(8) =8140a(9) =542542a(10) =72436a(11) =3311945a(12) =6050240a(13) =91668080a(14) =2505120a(15) =1972220235a(16) =92327460a(17) =5331136090a(18) =6360277000a(19) =320219686633a(20) =29187262016
External references
- oeis: A280882