12270214440
domain: N
Appears in sequences
- Numbers k such that k+1 and 3*k+1 are perfect squares.at n=9A045899
- For n > 5, a(n) = 15*a(n-1) - 15*a(n-2) + a(n-3); initial terms are 1, 3, 8, 120, 1680.at n=10A051047
- a(n) = 3*a(n-1) + 3*a(n-2) - a(n-3); a(0) = 1, a(1) = 0, a(2) = 3. a(n) = 4*{a(n-1)+(-1)^n}-a(n-2); a(0) = 1, a(1) = 0.at n=19A120892
- Denominators a(n) of Pythagorean approximations b(n)/a(n) to sqrt(3).at n=17A195499