a(n) = Sum_{i=0..n-1} (1 + (-1)^(n-1-i))/2 * Sum_{j=0..i} a(j)*a(i-j) for n > 0, with a(0) = 1.
A085139
a(n) = Sum_{i=0..n-1} (1 + (-1)^(n-1-i))/2 * Sum_{j=0..i} a(j)*a(i-j) for n > 0, with a(0) = 1.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =18a(5) =58a(6) =194a(7) =670a(8) =2370a(9) =8546a(10) =31298a(11) =116102a(12) =435346a(13) =1647418a(14) =6283394a(15) =24130174a(16) =93226242a(17) =362098050a(18) =1413098370a(19) =5538138182a(20) =21788069266a(21) =86016385274a(22) =340655956802
External references
- oeis: A085139