-1171

Appears in sequences

• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 393", based on the 5-celled von Neumann neighborhood.at n=21A271605
• a(n) = -2*a(n-1) + a(n-2) + a(n-3), a(0) = -1, a(1) = 3, a(2) = -9.at n=8A321173
• a(1) = 1; a(n) = -Sum_{k=1..n} a(k/gcd(n,k)).at n=23A343762