Number of permutations p of 1,2,...,n satisfying |p(i+2)-p(i)|<>3 and |p(j+3)-p(j)|<>2 for all i=1..n-2, j=1..n-3.
A189565
Number of permutations p of 1,2,...,n satisfying |p(i+2)-p(i)|<>3 and |p(j+3)-p(j)|<>2 for all i=1..n-2, j=1..n-3.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =12a(5) =36a(6) =174a(7) =708a(8) =4334a(9) =31424a(10) =263732a(11) =2503296a(12) =26844578a(13) =316692056a(14) =4090634212a(15) =57274447458a(16) =863488976620
External references
- oeis: A189565