-3443

Appears in sequences

• a(n) = 7 + 12*n - 6*n^2.at n=25A157517
• First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 395", based on the 5-celled von Neumann neighborhood.at n=39A271688
• Array of coefficients a(k,n) of the formal power series A(k,x) read by upwards antidiagonals, where A(k,x) = ((2*k+1)*x+sqrt(1+4*k*(k+1)*x^2))/(1-x^2), k>=0.at n=59A277930