20466

Appears in sequences

• Carlitz-Riordan q-Catalan numbers (recurrence version) for q=5.at n=4A015086
• Positive numbers k such that k and 3*k are anagrams in base 7 (written in base 7).at n=30A023069
• Triangle T(n,k), 0 <= k <= n, composed of k-Catalan numbers.at n=50A090182
• Expansion of (1 - x - 6*x^2)/(1 - x - 8*x^2).at n=10A100304
• Number of permutations of length n with exactly 8 occurrences of the pattern 2-13.at n=2A120816
• A007318 * [1, 2, 2, 3, 2, 3, 2, 3, 2, ...].at n=13A133124
• Triangle read by rows: T(n,k) (n>=0, 0<=k<=A002620(n-1)) is the number of permutations of [n] with k nestings.at n=51A263776
• Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of continued fraction 1/(1 - x/(1 - k*x/(1 - k^2*x/(1 - k^3*x/(1 - k^4*x/(1 - ...)))))).at n=49A290759
• Expansion of 1 / (1 - Sum_{i>=1, j>=1} x^(i*j*(j + 1)/2)).at n=14A327764
• Place two n-gons with radii 1 and 2 concentrically, forming an annular area between them. Connect all the vertices with line segments that lie entirely within that area. Then a(n) is the number of regions in that figure.at n=24A337700