13393689

Appears in sequences

• Riordan numbers: a(n) = (n-1)*(2*a(n-1) + 3*a(n-2))/(n+1).at n=20A005043
• Bisection of Motzkin sums (A005043).at n=10A099251
• Expansion of (sqrt(1+3*x) + sqrt(1-x))/(2*sqrt(1-x)).at n=21A099323
• a(n) = [x^n] (1 - 2*x - sqrt((1 - 3*x)/(1 + x)))/(2*x^3).at n=18A342912