2027520

Appears in sequences

• Triangle T(n,k) generalizing the tangent numbers.at n=17A064190
• 8-idempotent numbers: a(n) = binomial(n+8,8)*8^n.at n=4A141054
• a(n) = Product_{1 <= i < j <= n} (2^i + 2^j - 2).at n=3A203479
• a(n) is the number of subsets of {1..n} that contain exactly 4 odd numbers.at n=23A331419
• a(n) = (A003309(n)-1)*a(n-1) (n > 1), a(1) = 1, where A003309 are the ludic numbers.at n=8A377469
• a(n) = n^2 * 4^n * binomial(3*n, n).at n=4A378779
• a(n) = Sum_{k=0..floor(n/3)} 2^k * 3^(n-3*k) * binomial(k,4*(n-3*k)).at n=34A392074