130509

Appears in sequences

• a(n) = (Sum{k=0..n-1} a(k)) - a(n-3), with a(0)=0, a(1)=0, a(2)=1.at n=22A049856
• Number of strict partitions of 2n having an ordering of the parts in which no two neighboring parts have the same parity.at n=47A239882
• a(n) is the number of length-n ballot sequences whose reversals are also ballot sequences.at n=16A338418