-4511

Appears in sequences

• Define a sequence u(n) by u(1)=1; thereafter u(n) = f(n)/f(n-1) where f(n) = (-1)^(n+1)*A105750(n); sequence gives numerator(u(n)).at n=9A220448
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 189", based on the 5-celled von Neumann neighborhood.at n=35A270680
• Irregular triangle read by rows: For n >= 1, 0 <= k <= floor(n/2), T(n,k) is the minimal discriminant (in absolute value) of the number fields with signature r_1 = n - 2*k, r_2 = k.at n=9A343290