a(n)=c(n)+c(n-1)+2*c(n-2)+4*c(n-3)+8*c(n-4)+...+2^(n-2)*c(1)+2^(n-1)*c(0), where c(k) are the Catalan numbers (A000108).
A126221
a(n)=c(n)+c(n-1)+2*c(n-2)+4*c(n-3)+8*c(n-4)+...+2^(n-2)*c(1)+2^(n-1)*c(0), where c(k) are the Catalan numbers (A000108).
Terms
- a(0) =1a(1) =2a(2) =5a(3) =13a(4) =35a(5) =98a(6) =286a(7) =869a(8) =2739a(9) =8910a(10) =29754a(11) =101498a(12) =352222a(13) =1239332a(14) =4410204a(15) =15840813a(16) =57344451a(17) =208976022a(18) =765945954a(19) =2821516398a(20) =10439890026a(21) =38781926652a(22) =144580149924a(23) =540737349858
External references
- oeis: A126221