The number of weakly alternating bargraphs of semiperimeter n. A bargraph is said to be weakly alternating if its ascents and descents alternate. An ascent (descent) is a maximal sequence of consecutive U (D) steps.
A275448
The number of weakly alternating bargraphs of semiperimeter n. A bargraph is said to be weakly alternating if its ascents and descents alternate. An ascent (descent) is a maximal sequence of consecutive U (D) steps.
Terms
- a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =12a(6) =28a(7) =65a(8) =146a(9) =327a(10) =749a(11) =1756a(12) =4165a(13) =9913a(14) =23652a(15) =56687a(16) =136627a(17) =330969a(18) =804915a(19) =1963830a(20) =4805523a(21) =11793046a(22) =29019930a(23) =71589861a(24) =177006752a(25) =438561959a(26) =1088714711a(27) =2707615555a(28) =6745272783a(29) =16830750107
External references
- oeis: A275448