Number of permutations (p(1),p(2),...,p(n)) of (1,2,...,n) such that p(i)-i is in {-2,-1,4} for all i=1,...,n.
A376743
Number of permutations (p(1),p(2),...,p(n)) of (1,2,...,n) such that p(i)-i is in {-2,-1,4} for all i=1,...,n.
Terms
- a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =1a(7) =1a(8) =1a(9) =1a(10) =1a(11) =5a(12) =5a(13) =6a(14) =8a(15) =11a(16) =15a(17) =25a(18) =35a(19) =46a(20) =61a(21) =85a(22) =125a(23) =175a(24) =245a(25) =341a(26) =470a(27) =650a(28) =925a(29) =1300
External references
- oeis: A376743