Number of permutations of 1..n such that |p(i)-p(i-1)|>= 4 for i>1.
A179957
Number of permutations of 1..n such that |p(i)-p(i-1)|>= 4 for i>1.
Terms
- a(0) =1a(1) =1a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =2a(9) =72a(10) =1496a(11) =25384a(12) =399848a(13) =6231544a(14) =99133496a(15) =1634227958a(16) =28120703888a(17) =506599465896
External references
- oeis: A179957