1721764
domain: N
Appears in sequences
- Imaginary part of (1+2i)^n.at n=18A006496
- a(n) = 5^n*sin(2n*arctan(1/2)) or numerator of tan(2n*arctan(1/2)).at n=8A066770
- Largest leg in right triangle with relatively prime sides and hypotenuse 5^n.at n=8A067312
- Numbers k such that (k^2 - 14)/2 is a square.at n=15A077447
- Let (A,B)=(a(2*n),a(2*n+1)), then (A,B) is (even,odd), gcd(A,B)=1 and A^2 + B^2 = 5^n. Note: a(0)=0.at n=36A098122
- Expansion of 1/(1 - 4*x + 5*x^2).at n=17A099456
- Real part of (4 + 3i)^n.at n=9A139030
- Values of y such that x^2 + y^2 = 5^n with x and y coprime and 0 < x < y.at n=17A230711