a(n) = Sum_{k=floor(n/4)..R} C(k, m*k - (-1)^n*(R - k)) * C(k + 1, m*(k + 2) - (-1)^n*(R - k + 1)) where m = (n + 1) mod 2 and R = (n + m - 3)/2 for n > 0 and a(0) = 1.
A202411
a(n) = Sum_{k=floor(n/4)..R} C(k, m*k - (-1)^n*(R - k)) * C(k + 1, m*(k + 2) - (-1)^n*(R - k + 1)) where m = (n + 1) mod 2 and R = (n + m - 3)/2 for n > 0 and a(0) = 1.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =1a(4) =1a(5) =2a(6) =3a(7) =4a(8) =7a(9) =10a(10) =16a(11) =24a(12) =39a(13) =58a(14) =95a(15) =143a(16) =233a(17) =354a(18) =577a(19) =881a(20) =1436a(21) =2204a(22) =3590a(23) =5534a(24) =9011a(25) =13940a(26) =22691a(27) =35213a(28) =57299a(29) =89162
External references
- oeis: A202411