a(n) = Sum((-1)^(n-i)*binomial(3i,i)*binomial(n+2i,3i)*2^i/(2i+1),i=0..n).
A153232
a(n) = Sum((-1)^(n-i)*binomial(3i,i)*binomial(n+2i,3i)*2^i/(2i+1),i=0..n).
Terms
- a(0) =1a(1) =1a(2) =5a(3) =31a(4) =217a(5) =1637a(6) =12985a(7) =106767a(8) =901857a(9) =7779321a(10) =68238029a(11) =606829087a(12) =5458425065a(13) =49575244557a(14) =454002681969
External references
- oeis: A153232