Sum of the sizes of the second blocks in all set partitions of {1,2,...,n}.
A270494
Sum of the sizes of the second blocks in all set partitions of {1,2,...,n}.
Terms
- a(0) =1a(1) =5a(2) =21a(3) =88a(4) =387a(5) =1816a(6) =9123a(7) =48971a(8) =279855a(9) =1695902a(10) =10856879a(11) =73173016a(12) =517597981a(13) =3831970709a(14) =29617983433a(15) =238460465120
External references
- oeis: A270494