The number of valleys of width 1 (i.e., DHU configurations, where U=(0,1), H(1,0), D=(0,-1)) in all bargraphs of semiperimeter n (n>=2).
A273722
The number of valleys of width 1 (i.e., DHU configurations, where U=(0,1), H(1,0), D=(0,-1)) in all bargraphs of semiperimeter n (n>=2).
Terms
- a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =7a(6) =34a(7) =143a(8) =558a(9) =2083a(10) =7559a(11) =26913a(12) =94547a(13) =328943a(14) =1136218a(15) =3903245a(16) =13352270a(17) =45524764a(18) =154811018a(19) =525345268a(20) =1779722313a(21) =6020903806a(22) =20346143381a(23) =68691126090a(24) =231732871764a(25) =781268589267
External references
- oeis: A273722