a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026615.
A026957
a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026615.
Terms
- a(0) =1a(1) =6a(2) =35a(3) =154a(4) =613a(5) =2362a(6) =9028a(7) =34510a(8) =132241a(9) =508210a(10) =1958460a(11) =7565906a(12) =29292820a(13) =113633930a(14) =441579702a(15) =1718642278a(16) =6698377449a(17) =26139863330a(18) =102125977396a(19) =399415127682
External references
- oeis: A026957