31920

Appears in sequences

• a(n) = (3*n+4)*(n+3)!/24.at n=5A005460
• Area of more than one Pythagorean triangle.at n=25A009127
• Let a,b,c,...k be all divisors of n; a(n) = (a+1)*(b+1)*...*(k+1).at n=17A020696
• a(n) = T(n,n-3), where T is the array in A026374.at n=37A026382
• Triangular array a(n,k) = (1/k)*Sum_{i=0..k} (-1)^(k-i)*binomial(k,i)*i^n; n >= 1, 1 <= k <= n, read by rows.at n=33A028246
• Number of proper factorizations of p1^n*p2^4, where p1 and p2 are distinct primes.at n=18A031127
• Number of ways to partition n labeled elements into 6 pie slices.at n=2A032180
• Triangle of coefficients of polynomials enumerating trees with n labeled nodes by inversions.at n=45A052121
• Number of k-simplices in the first derived complex of the standard triangulation of an n-simplex. Equivalently, T(n,k) is the number of ascending chains of length k+1 of nonempty subsets of the set {1, 2, ..., n+1}.at n=25A053440
• Triangle of coefficients of polynomials H(n,x) formed from the first (n+1) terms of the power series expansion of ( -x/log(1-x) )^(n+1), multiplied by n!.at n=30A075263
• Absolute value of determinant of n X n matrix whose entries are the integers from 1 to n^2 spiraling outward, ending in a corner.at n=4A079340
• Numbers that can be expressed as the difference of the squares of primes in exactly eleven distinct ways.at n=4A092007
• Triangle read by rows of coefficients used to generate diagonals of ordered factorizations as displayed in A098348.at n=18A098384
• When the n-th term of this sequence is added to or subtracted from the square of the n-th prime of the form 4k + 1 (i.e., A002144(n)), the result in both cases is a square.at n=19A114200
• Icosagonal numbers divisible by 20.at n=12A117798
• Triangle read by rows: T[n,k] = the number of ascending runs of length at least k in the permutations of [n] for k <= n.at n=30A122844
• Triangle read by rows, 0 <= k <= n, T(n,k) = Sum_{j=0..n} A(n,j)*binomial(n-j,k) where A(n,j) are the Eulerian numbers A173018.at n=30A130850
• Number of walks of length 2*n+2 from origin to (1,1,0) on a cubic lattice.at n=3A135394
• Expansion of the exponential generating function 1 - log(1 - x*(exp(z) - 1)), triangle read by rows, T(n,k) for n >= 0 and 0 <= k <= n.at n=42A142071
• a(n) = n!*A001515(n-1) with a(0) = 1.at n=5A143990