Number of arrays of n+2 integers in -1..1 with sum zero and the sum of every adjacent pair being odd.
A202069
Number of arrays of n+2 integers in -1..1 with sum zero and the sum of every adjacent pair being odd.
Terms
- a(0) =2a(1) =4a(2) =2a(3) =0a(4) =6a(5) =12a(6) =6a(7) =0a(8) =20a(9) =40a(10) =20a(11) =0a(12) =70a(13) =140a(14) =70a(15) =0a(16) =252a(17) =504a(18) =252a(19) =0a(20) =924a(21) =1848a(22) =924a(23) =0a(24) =3432a(25) =6864a(26) =3432a(27) =0a(28) =12870a(29) =25740
External references
- oeis: A202069