193700403
domain: N
Appears in sequences
- a(n) = 3^n*(3^n-1)/2.at n=9A026121
- Number of reversible strings with n beads of 3 colors. If more than 1 bead, not palindromic.at n=17A032086
- Number of primitive (aperiodic) palindromic structures using a maximum of three different symbols.at n=38A056477
- a(n) = A000217(n^3) - n^3.at n=27A085744
- a(n) = n! * Sum_{i+2j+3k=n} 1/(i!*(2j)!*(3k)!).at n=19A094717
- Expansion of x^2/((3*x-1)*(3*x^2-1)).at n=19A167993
- Cogrowth sequence of the 18-element group S3 X C3 = <S,T,U | S^3, T^2, U^3, (ST)^2, [S,U], [T,U]>.at n=20A378109