-597551756

Appears in sequences

• Imaginary part of (1+2i)^n.at n=26A006496
• a(n) = 5^n*sin(2n*arctan(1/2)) or numerator of tan(2n*arctan(1/2)).at n=12A066770
• Expansion of 1/(1 - 4*x + 5*x^2).at n=25A099456
• Real part of (4 + 3i)^n.at n=13A139030