Number of permutations of 0..(n-1) representable as 1,2,1-weighted consecutive sums of 3 adjacent elements of a sequence of n+2 nonnegative integers.
A180213
Number of permutations of 0..(n-1) representable as 1,2,1-weighted consecutive sums of 3 adjacent elements of a sequence of n+2 nonnegative integers.
Terms
- a(0) =1a(1) =2a(2) =4a(3) =6a(4) =12a(5) =36a(6) =102a(7) =324a(8) =972a(9) =3190a(10) =12610a(11) =50254a(12) =214510a(13) =1000260a(14) =4848796a(15) =24798190a(16) =134817190
External references
- oeis: A180213