21510

Appears in sequences

• Place n equally-spaced points around a circle and join every pair of points by a chord; this divides the circle into a(n) regions.at n=29A006533
• Numerators of continued fraction convergents to sqrt(895).at n=5A042730
• G.f. satisfies A(x) = 1 + x*A(x)*A(x^2)*A(x^3)*...*A(x^n)*...at n=17A091865
• Triangle read by rows: T(n,k) is the number of Schroeder paths of length 2n and having k platforms (i.e., UHD, UHHD, UHHHD, ..., where U=(1,1), D=(1,-1), H=(2,0)).at n=27A104546
• Triangle Q, read by rows, such that Q^2 transforms column k of Q^2 into column k+1 of Q^2, so that column k of Q^2 equals column 0 of Q^(2*k+2), where Q^2 denotes the matrix square of Q.at n=22A113350
• Column 1 of triangle A113350, also equals column 0 of A113340^4.at n=5A113351
• Triangle, read by rows, given by the product Q^-1*P^2, where the triangular matrices involved are P = A113340 and Q = A113350.at n=30A113368
• Triangle T(n,k) read by rows: matrix inverse of A106246.at n=21A167196
• First column of A167196.at n=6A167199
• Third accumulation array, T, of the natural number array A000027, by antidiagonals.at n=62A185508
• Record (maximal) gaps between prime 5-tuples (p, p+2, p+6, p+8, p+12).at n=4A201073
• Number of (n+1) X (3+1) 0..1 arrays with nondecreasing max(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.at n=7A250578
• Number of (n+2)X(3+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 2 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 2 4 6 or 7.at n=5A252518
• Number of (n+2) X (6+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 2 4 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 2 4 6 or 7.at n=2A252521
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 2 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 2 4 6 or 7.at n=30A252523
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 2 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 2 4 6 or 7.at n=33A252523
• Number T(n,k) of labeled cyclic chord diagrams having n chords and minimal chord length k (or k=0 if n=0); triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=51A324429
• Number of labeled cyclic chord diagrams with n chords such that the minimal chord length equals six.at n=3A324450
• Triangle read by rows: T(n,k) is the number of series-reduced rooted trees whose leaves are sets of colors with a total of n elements using exactly k colors.at n=19A330763
• a(n) is the number of solid (3D) partitions of n with 2 layers and second layer a plane partition of 3.at n=11A381265