281185

Appears in sequences

• G.f.: 1/(1-2x-15x^2)^(1/2); also, a(n) is the central coefficient of (1+x+4x^2)^n.at n=9A084605
• Vertically symmetrical dates DDMMYY ("condensed European notation") considered as numbers, in increasing order.at n=9A107276
• Triangle read by rows, T(n,k) = 2^k*GegenbauerC(k,-n,-1/4), for n>=0 and 0<=k<=n.at n=54A272868
• Triangle read by rows: T(n,k) = number of colored weighted Motzkin paths ending at (n,k).at n=45A293171