22737

Appears in sequences

• a(n) = ((2*n-1)!/(2*n!*(n-2)!))*((n^3-3*n^2+2*n+2)/(n^2-1)).at n=5A002739
• Denominators of numbers occurring in continued fraction connected with expansion of gamma function.at n=4A005147
• a(1)=1, a(n) = n*8^(n-1) + a(n-1).at n=4A014921
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-1)/2.at n=19A047174
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-2)/2.at n=19A047185
• 1+2n+3n^2+4n^3+5n^4.at n=8A056579
• a(n) = n^3 + n^2 + 1.at n=28A098547
• 45-gonal numbers: n*(43*n-41)/2.at n=32A098924
• Triangle read by rows: T(n,k) is number of Grand Motzkin paths of length n having k returns to the x-axis from above (i.e., d steps hitting the x-axis).at n=52A109195
• a(n) is the numerator of the sum of the reciprocals of the positive integers k, k<=n, where every positive integer <= k and coprime to k is also coprime to n.at n=33A126261
• First row of spectral array W(gamma+1).at n=20A250253
• Small positive integer solutions of the simultaneous equations y = ax + b and y^2 = ax^3 + b.at n=27A262598
• Number of integers in n-th generation of tree T(-1/3) defined in Comments.at n=33A274148
• Irregular triangle read by rows: T(n,m) = number of lattice paths of type A^Q terminating at point (n, m).at n=48A291083
• Number of symmetric maximal irredundant sets in the n-path graph.at n=52A291444
• Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=11A318070
• Triangle T(n,k) (n >= k >= 0) read by rows: T(n,0) = (1+(-1)^n)/2; for k>=1, set T(0,k) = 0, S(n,k) = binomial(n,k)*binomial(n+k+1,k), and for n>=1, T(n,k) = S(n,k)-T(n-1,k).at n=33A331432
• a(n) = binomial(n, n/2 - 1/4 + (-1)^n/4)*hypergeom([-n/4 - 1/8 + (-1)^n/8, -n/4 + 3/8 + (-1)^n/8], [n/2 + 7/4 + (-1)^n/4], 4).at n=13A344394
• a(n) = binomial(2*n + 1, n)*hypergeom([-(n + 1)/2, -n/2], [n + 2], 4).at n=6A344396
• Number of vertex cuts in the n-triangular grid graph.at n=4A362520