1956244

Appears in sequences

• a(n) = 4*a(n-1) - a(n-2) with a(0) = 2, a(1) = 4.at n=11A003500
• Arises from generalized Lucas-Lehmer test for primality.at n=8A018844
• Array T(n,k) read by antidiagonals: T(n,k) = sum(i=0...n, (-1)^(n+i) * C(n+i,2i) * n/(2i+1) * k^(2i+1) ), n>0, k>1.at n=23A231123
• Sides of (Heronian) triangles where sides are consecutive integers and area is an integer.at n=31A242497