109824

Appears in sequences

• Number of perfect matchings (or domino tilings) in D_4 X P_(n-1).at n=12A003757
• a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 2. Also a(n) = (2^n)*C(n-1), where C = A000108 (Catalan numbers).at n=7A025225
• Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= (n+2)/3.at n=36A048081
• Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= (n+3)/3.at n=36A048092
• Triangle of coefficients of Chebyshev's U(n,2*x-1) polynomials (exponents of x in increasing order).at n=48A053124
• Seventh column of Lanczos triangle A053125 (decreasing powers).at n=3A054325
• a(n) = 2^(n-7)*binomial(n,7). Number of 7D hypercubes in an n-dimensional hypercube.at n=6A054851
• Second column of triangle A055584.at n=10A055585
• a(n) = 2^(n-1)*binomial(2*n-1, n).at n=6A069720
• A transform of binomial(n,6).at n=7A082140
• Triangle read by rows: T(n,m) = 4^m * (2*n+1)! / ( (2*n - 2*m + 1)! * (2*m)! ), row n has n+1 terms.at n=24A085840
• Triangle: row #n has n+1 terms. T(n,m) = 4^m (2n+1)! / ( (2n-2m)! (2m+1)! ).at n=24A085841
• E.g.f. BesselI(0,2*sqrt(2)*x) + BesselI(1,2*sqrt(2)*x)/sqrt(2).at n=13A098660
• Expansion of (sqrt(1-8*x^2)+8*x^2+2*x-1)/(2*x*sqrt(1-8*x^2)).at n=15A103973
• A sequence related to Catalan numbers A000108.at n=8A115125
• Triangle of coefficients for polynomials used for the column g.f.s of triangle A116880, called CM(1,2).at n=43A117505
• Riordan array ((3-sqrt(1+8x))/2, (sqrt(1+8x)-1)/4).at n=36A122440
• A "king chicken" in a tournament graph (a directed labeled graph on n nodes with a single arc between every pair of nodes) is a player A who for any other player B either beats B directly or beats someone who beats B. Sequence gives total number of king chickens in all 2^(n(n-1)/2) tournaments.at n=5A123553
• If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 6-subsets of X containing none of X_i, (i=1,...n).at n=7A130812
• a(n) = (n-2)^4 - a(n-1) - a(n-2), with a(1) = a(2) = 0.at n=24A152729