1129438

Appears in sequences

• a(2n+1) = a(2n) + a(2n-1), a(2n) = 2*a(2n-1) + a(2n-2); a(n) = n for n = 0, 1.at n=22A048788
• a(n) = 4*a(n-1) - a(n-2), with a(0) = 0, a(1) = 2.at n=11A052530
• Limit of the sequence obtained from S(0) = (1,1) and, for n > 0, S(n) = I(S(n-1)), where I consists of inserting, for i = 1, 2, 3..., the term a(i) + a(i+1) between any two terms for which 7*a(i+1) <= 11*a(i).at n=21A082630
• The pairs (x,y) such that (x^2 + y^2)/(x*y + 1) is a perfect square, i.e., 4.at n=21A162959
• The pairs (x,y) such that (x^2 + y^2)/(x*y + 1) is a perfect square, i.e., 4.at n=22A162959
• a(n) = a(n-1) + (if a(n-1) is odd a(n-2) else a(n-3)) with a(0) = 0, a(1) = 1.at n=33A254308