a(n) = Sum_{p in P} binomial(H(2,p),2), where P is the set of partitions of n, and H(2,p) = number of hooks of size 2 in p.
A301313
a(n) = Sum_{p in P} binomial(H(2,p),2), where P is the set of partitions of n, and H(2,p) = number of hooks of size 2 in p.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =1a(6) =6a(7) =7a(8) =18a(9) =24a(10) =49a(11) =66a(12) =116a(13) =158a(14) =255a(15) =346a(16) =525a(17) =707a(18) =1030a(19) =1374a(20) =1936a(21) =2560a(22) =3519a(23) =4608a(24) =6207a(25) =8056a(26) =10673a(27) =13735a(28) =17942a(29) =22906
External references
- oeis: A301313