18656

Appears in sequences

• a(n+3) = a(n+2) + a(n+1) + a(n) - 4.at n=17A000803
• Rook polynomials.at n=15A004306
• a(n) is least k such that k and 8k are anagrams in base n (written in base 10).at n=14A023100
• Open 3-dimensional ball numbers (version 4): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (1/2, 1/2, 1/2).at n=33A053596
• a(n) = (2*n-1)*(n^2 -n +2)/2.at n=26A063488
• 3-apexes of Omega: numbers k such that Omega(k-3) < Omega(k-2)< Omega(k-1) < Omega(k) > Omega(k+1) > Omega(k+2) > Omega(k+3), where Omega(m) = the number of prime factors of m, counting multiplicity.at n=4A076760
• Triangle read by rows: T(n,k) (1<=k<=n) given by T(n, 1) = T(n,n) = 1, otherwise T(n, k) = (m*n-m*k+1)*T(n-1,k-1) + (m*k-m+1)*T(n-1,k), where m = 5.at n=22A142460
• Triangle read by rows: T(n,k) (1<=k<=n) given by T(n, 1) = T(n,n) = 1, otherwise T(n, k) = (m*n-m*k+1)*T(n-1,k-1) + (m*k-m+1)*T(n-1,k), where m = 5.at n=26A142460
• a(n) = (3*n+1)*(5*n+1).at n=35A144459
• a(n) = 2662*n + 22.at n=6A157613
• Number of (n+2) X (6+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7.at n=6A252530
• Number of (7+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7.at n=5A252539
• Total number of n-digit positive integers with multiplicative digital root value 5.at n=7A263479
• Number of length-4 0..n arrays with no following elements greater than or equal to the first repeated value.at n=10A267233
• G.f. satisfies: A(x) = Sum_{n>=0} x^n * A(x)^(2*n^2) / (1 + x*A(x)^(2*n))^n.at n=7A301928
• G.f.: Sum_{n>=0} (n+1) * x^n * (1 + x^n)^n.at n=70A326002
• Total number of interior vertices in the multigraphs of all unoriented series-parallel networks with n edges.at n=8A339286
• E.g.f. A(x) satisfies A(x) = Sum_{k>=0} x^k/k! * A(k^2*x).at n=5A385547