-15994428

Appears in sequences

• Expansion of 1/(1 + 2*x - x^2).at n=19A077985
• Expansion of 2+(1-2*x)/(-1+2*x+x^2).at n=21A176981
• a(n) = -2*a(n-1) + a(n-2) for n > 2, with a(0) = a(1) = 1, a(2) = 0.at n=22A215936