a(n) = P(n+1, n+1) where P(n, m) = P(n, m-1) + P(n-1, m + f(m-n)) for n < m with P(n, m) = P(n-1, m) for 0 <= m <= n and P(0, m) = 1 for m >= 0 and where f(n) = [(n mod 4) > 0].

A376317

a(n) = P(n+1, n+1) where P(n, m) = P(n, m-1) + P(n-1, m + f(m-n)) for n < m with P(n, m) = P(n-1, m) for 0 <= m <= n and P(0, m) = 1 for m >= 0 and where f(n) = [(n mod 4) > 0].

Terms

    a(0) =1a(1) =2a(2) =6a(3) =23a(4) =100a(5) =466a(6) =2270a(7) =11413a(8) =58776a(9) =308473a(10) =1643922a(11) =8872220a(12) =48393710a(13) =266357916a(14) =1477471248a(15) =8251090171a(16) =46353709956a(17) =261783417427

External references