Number of permutations of length n with exactly 4 rising or falling successions.
A086855
Number of permutations of length n with exactly 4 rising or falling successions.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =2a(6) =22a(7) =226a(8) =2198a(9) =22120a(10) =236968a(11) =2732268a(12) =33940644a(13) =453148422a(14) =6480322210a(15) =98907371822
External references
- oeis: A086855