447744

Appears in sequences

• a(n) contains n digits (either '4' or '7') and is divisible by 2^n.at n=5A053332
• Generalized Catalan triangle, based on C(2,2; n) = A064340(n).at n=33A067298
• Generalized Catalan triangle A067298 with row reversion.at n=30A067304
• O.g.f. A(x,y) satisfies: [x^n] exp( n * x*A(x,y) ) * (n + y - A(x,y)) = 0 for n > 0.at n=23A305109
• Product_{n>=1} 1 / (1 - x^n)^(a(n)/n!) = 1 + arctan(x).at n=9A354117