6531840

Appears in sequences

• a(n) = n! * n(n-1)/4.at n=9A001809
• Triangle of D'Arcais numbers.at n=45A008298
• Triangle of coefficients of Laguerre polynomials L_n(x) (powers of x in decreasing order).at n=52A021010
• a(n) = (n-1)! * sigma(n).at n=9A038048
• Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j)*9^j.at n=31A038239
• Triangle whose (i,j)-th entry is binomial(i,j)*9^(i-j)*4^j.at n=32A038294
• a(n) = 2*n*n!.at n=9A052582
• Triangle of generalized Stirling numbers.at n=43A061691
• Expansion of Lambert W function in powers of log(log(x))/log(x).at n=43A073315
• Array of coefficients of denominator polynomials of the n-th approximation of the continued fraction x/(1+x/(2+x/(3+..., related to Laguerre polynomial coefficients.at n=38A084950
• a(1) = 3, a(n) = smallest multiple of a(n-1) such that 10*a(n) + 1 is prime.at n=15A089325
• A convolution triangle of numbers obtained from A036224.at n=22A132166
• Triangle read by rows: number of nilpotent partial transformations (of an n-element set) of height r (height(alpha) = |Im(alpha)|), 0 <= r < n.at n=43A141618
• Triangle read by rows: T(n,k) is the number of fixed-point-free involutions of {1,2,...,2n} having k cycles with entries of opposite parities (0 <= k <= n).at n=52A161119
• Triangle read by rows: T(n,k) is the number of fixed-point-free involutions of {1,2,...,2n} having k cycles with entries of the same parity (0 <= k <= 2*floor(n/2)).at n=43A161121
• Triangle T(n, k) = binomial(n, k)*( n!/k! if floor(n/2) >= k otherwise n!/(n-k)! ), read by rows.at n=47A174298
• Triangle T(n, k) = binomial(n, k)*( n!/k! if floor(n/2) >= k otherwise n!/(n-k)! ), read by rows.at n=52A174298
• Number of ways to place 7 nonattacking bishops on an n X n toroidal board.at n=8A178140
• Number of non-attacking placements of 7 rooks on an n X n board.at n=8A179062
• 1/8 the number of triangular nXnXn arrays of integers in 1..8 with no element or any of its neighbors having the same value.at n=4A180371