Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/4)] (4-way heap).
A178009
Number of permutations of 1..n with no element e[i>=2]<e[1+floor((i-2)/4)] (4-way heap).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =6a(5) =24a(6) =60a(7) =240a(8) =1260a(9) =8064a(10) =36288a(11) =241920a(12) =1995840a(13) =19160064a(14) =124540416a(15) =1162377216a(16) =13076743680a(17) =167382319104
External references
- oeis: A178009