Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/2)] (2-way heap).
A178012
Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/2)] (2-way heap).
Terms
- a(0) =1a(1) =2a(2) =7a(3) =44a(4) =394a(5) =5160a(6) =95772a(7) =2070282a(8) =54033576a(9) =1768770384a(10) =74057667588
External references
- oeis: A178012