46737

Appears in sequences

• Triangular matrix T, read by rows, where row n equals row (n-1) of T^(n-1) after appending '1' for the main diagonal.at n=28A101479
• Column 0 of triangular matrix T=A101479, in which row n equals row (n-1) of T^(n-1) followed by '1'.at n=7A101481
• a(0)=1, a(1)=9, a(n) = 18*a(n-1) - 9*a(n-2) for n>1.at n=4A165232
• G.f.: 1/(1 - x/(1 - x^4/(1 - x^7/(1 - x^10/(1 - x^13/(1 - x^16/(1 -...- x^(3*n-2)/(1 -...)))))))), a continued fraction.at n=35A206737
• Size of the equivalence class of S_n containing the identity permutation under transformations of positionally adjacent elements of the form abc <--> acb <--> bac where a<b<c.at n=9A212417
• Numbers of the form 6^j + 9^k, for j and k >= 0.at n=31A226830
• a(n) = Sum_{k=0..floor(n/3)} (n-3*k)^(n-2*k).at n=6A353014
• Expansion of Sum_{k>=0} (k * x * (1 + x^3))^k.at n=6A360728
• Number of even-length integer partitions of n with integer median.at n=47A361653
• Triangle read by rows: T(n,k) is the number of nonisomorphic semigroups with n elements whose center contains k elements.at n=33A391159