171006

Appears in sequences

• a(n) = 3^n - 3*2^n + 3.at n=11A001117
• Number of 3 X 3 integer matrices with elements in the range [ -n,n ] which represent a four-fold rotation. Also the sequence for the corresponding four-fold rotoinversions.at n=6A053173
• Number of primitive (aperiodic) words of length n which contain exactly three different symbols.at n=10A056268
• Number of palindromes of length n using exactly three different symbols.at n=20A056454
• Number of palindromes of length n using exactly three different symbols.at n=21A056454
• Number of periodic palindromes using exactly three different symbols.at n=20A056489
• A(k,3) where A(k,n) = Sum_{m=1..k} (-1)^(m+1) *binomial(n,m)*m^k.at n=10A179483
• Triangle read by rows: T(n, k) = t(n-k, k), where t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), and f(n) = 4*n + 3.at n=22A257621
• Triangle read by rows: T(n, k) = t(n-k, k), where t(0,0) = 1, t(n,m) = 0 if n < 0 or m < 0, else t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), and f(n) = 4*n + 3.at n=26A257621