30849

Appears in sequences

• a(n) = Sum_{i=0..n} T(i,n-i), array T as in A049735.at n=24A049736
• Expansion of (1-x)/(1+x+2*x^2+x^3).at n=42A078051
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x + 31)^2 = y^2.at n=13A118674
• a(0)=0, a(1)=1, a(2)=2 and a(n) = a(n-1) - 2a(n-2) + a(n-3).at n=43A166117
• Expansion of (1-2*x^2-sqrt(1-4*x^2-4*x^3))/(2*x*sqrt(1-4*x^2-4*x^3)).at n=15A234269
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 291", based on the 5-celled von Neumann neighborhood.at n=36A271131
• Composite squarefree integers for which the sum of the squares of their factors is a square.at n=21A379780