66430

Appears in sequences

• a(n) = (9^n - 1)/8.at n=6A002452
• Coloring a circuit with 4 colors.at n=11A006342
• Triangle of central factorial numbers 4^k T(2n+1, 2n+1-2k).at n=26A008958
• Triangle of Gaussian binomial coefficients [ n,k ] for q = 9.at n=22A022173
• Triangle of Gaussian binomial coefficients [ n,k ] for q = 9.at n=26A022173
• Gaussian binomial coefficients [ n,5 ] for q = 9.at n=1A022256
• Numbers k such that k^2 is palindromic in base 9.at n=26A029994
• Base-3 digits are, in order, the first n terms of the periodic sequence with initial period 1,0.at n=10A033113
• Numbers whose base-3 representation has exactly 11 runs.at n=0A043591
• Numbers n such that number of runs in the base 3 representation of n is congruent to 1 mod 10.at n=20A043816
• Numbers that are repdigits in base 9.at n=41A048334
• a(n) = 111111 in base n.at n=8A053700
• a(n) = floor(3^n / n^3).at n=17A062278
• Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=34A069674
• Numbers of the form (3^{mr}-1)/(3^r-1) for positive integers m, r.at n=26A076270
• Numbers of the form (9^{mr}-1)/(9^r-1) for positive integers m, r.at n=10A076288
• Sum of digits of numbers between 0 and (4/9)*(10^n-1).at n=4A089906
• Triangle read by rows: T(n,k) = (n+1,k)-th element of (M^9-M)/8, where M is the infinite lower Pascal's triangle matrix, 1<=k<=n.at n=15A096043
• a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, k-1)*2^(n-k-1)*(3/2)^(k-1).at n=12A099583
• If n mod 2 = 0 then (3^(n+3)-19)/8 else (3^(n+3)-1)/8.at n=9A116973