a(n) = binomial(3*n,n)/(2*n + 1) - 2*binomial(3*(n - 1),n - 1)/(2*n - 1) for n > 0 with a(0) = 1.
A336945
a(n) = binomial(3*n,n)/(2*n + 1) - 2*binomial(3*(n - 1),n - 1)/(2*n - 1) for n > 0 with a(0) = 1.
Terms
- a(0) =1a(1) =-1a(2) =1a(3) =6a(4) =31a(5) =163a(6) =882a(7) =4896a(8) =27759a(9) =160149a(10) =937365a(11) =5553210a(12) =33237828a(13) =200696356a(14) =1221105376a(15) =7479222624a(16) =46079243631a(17) =285373035417
External references
- oeis: A336945