20076

Appears in sequences

• Number of partitions of 3n into n parts from the set {0, 1, ..., 6} (repetitions admissible).at n=27A001977
• Number of 5-tuples of different integers from [ 1,n ] with no global factor.at n=20A015640
• a(0)=1, for n>=1 a(n) = Sum_{k=0..n} 5^k*N(n,k) where N(n,k) = C(n,k)*C(n,k+1)/n are the Narayana numbers (A001263).at n=6A078009
• a(n) = N(6,n), where N(6,x) is the 6th Narayana polynomial.at n=5A090199
• G.f.: Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 5.at n=41A091773
• a(n) = (1/n) * Sum_{k=0..n-1} C(n,k) * C(n,k+1) * (n-1)^k.at n=5A099169
• Series reversion of x/(1+6x+5x^2).at n=6A127848
• Number of reduced 3 X 3 magilatin squares with largest entry n.at n=16A174018
• Number of strictly increasing arrangements of 6 numbers in -(n+4)..(n+4) with sum zero.at n=11A188184
• Number of -n..n arrays x(0..2) of 3 elements with zeroth through 2nd differences all nonzero.at n=13A199944
• Triangle derived from an array of f(x), Narayana polynomials.at n=60A204057
• Triangle read by rows, T(n,k) = 2^k*GegenbauerC(k,-n,-1/4), for n>=0 and 0<=k<=n.at n=51A272868
• a(n) = 54*n^2 - 78*n + 36.at n=20A277983
• Expansion of Product_{k>=1} 1/(1 - k*x^k)^(k^2).at n=8A285241
• Triangle read by rows: T(n,k) = number of colored weighted Motzkin paths ending at (n,k).at n=48A293171
• Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of Product_{j>=1} 1/(1 - j*x^j)^(j^k).at n=63A294589
• Expansion of 1/(1 - x) * Product_{k>=0} 1/(1 - x^(4^k))^(4^(k+1)).at n=12A321345
• Number of excursions of length n with Motzkin-steps avoiding the consecutive steps UU, UD, HH and DU.at n=29A329689
• Numbers k such that A334943(k) = 1.at n=16A335773
• Integers k such that there exists an integer 0<m<k such that (1/sigma(m)^2 + 1/sigma(k)^2)*(m+k)^2 = 1.at n=8A383964