2017356

Appears in sequences

• a(n) = 3*binomial(4*n-1, n-1)/(4*n-1).at n=8A006632
• a(n) = floor( binomial(n,8)/9).at n=34A011845
• Number of necklaces with 9 black beads and n-9 white beads.at n=26A032194
• a(n) = ceiling(binomial(n,9)/n).at n=34A053733
• Length of lists created by n substitutions k -> Range[k+1,1,-3] starting with {1}, counting down from k+1 to 1 step -3.at n=25A084080
• a(3n+k) = (k+1)*binomial(4n+k, n)/(3n+k+1), where k is n reduced mod 3.at n=26A124753
• Triangle, read by rows, defined by: T(n,k) = 1/((k+1)n-1) binomial((k+1)n-1,n) for n,k>0.at n=57A162382
• G.f. A(x) satisfies: A(x*(1+x)^3) = 1 + x.at n=9A171790
• a(n) = lcm(n, n+1, n+2, n+3, n+4, n+5, n+6, n+7)/840.at n=29A188897
• Number of aperiodic necklaces (Lyndon words) with 9 black beads and n white beads.at n=26A263318
• 3-parking triangle T(r, i, 3) read by rows: T(r, i, k) = (r + 1)^(i-1)*binomial(k*(r + 1) + r - i - 1, r - i) with k = 3 and 0 <= i <= r.at n=36A329059
• Triangle read by rows. T(n,k) = Sum_{j=0..k} binomial(k-j+2, 2)*T(n-1, j), for n>=0, 0<=k<=n, with T(0,0)=1 and T(n,n)=0 for n>0.at n=53A339350
• Expansion of g.f. A(x) satisfying A(x) = 1 + x*(3*A(x)^2 + A(-x)^2)/4.at n=17A369082
• Number of subsets of 9 integers between 1 and n such that their sum is 3 modulo n.at n=25A381351
• a(n) = 6 * (4*n)! / ((n+1)! * (3*n+1)!).at n=9A384585