140400

Appears in sequences

• Expansion of Eisenstein series E_4(q) (alternate convention E_2(q)); theta series of E_8 lattice.at n=8A004009
• a(n) = binomial(2*n, n) mod ((n+1)*(n+2)*(n+3)*(n+4)).at n=22A065346
• Unreduced numerators of the elements T(n,k)/(n-k)!, read by rows, of the triangular matrix P^-1, which is the inverse of the matrix defined by P(n,k) = (-k^2-k)^(n-k)/(n-k)! for n >= k >= 1.at n=32A103244
• Numbers k whose digits can be divided into two contiguous parts, k = concatenate(x, y), such that k = |x^2 - y^2|.at n=9A113797
• a(n) = gcd(n!, binomial(2n,n)).at n=23A135322
• a(n) = n*(n+1)*(n+2)*(n+3)/3.at n=24A162668
• Numbers k which are concatenations k = x//y such that y^2 - x^2 = k.at n=5A162700
• Central binomial coefficient CB(n) purged of all primes exceeding (n+1)/2.at n=45A212791
• Number of length-n 0..4 arrays connected end-around, with no sequence of L<n elements immediately followed by itself (periodic "squarefree").at n=8A215224
• Integer areas A of integer-sided cyclic quadrilaterals such that the circumradius is of prime length.at n=32A230136
• a(n) = binomial(2*n, n) / Product(p prime | n < p <= 2*n).at n=23A263931
• Heinz numbers of integer partitions whose sum of reciprocals squared is an integer.at n=40A318588
• Numbers with exactly four distinct exponents in their prime factorization, or four distinct parts in their prime signature.at n=5A323025
• a(n) is the permanent of the n X n symmetric matrix M(n) defined by M[i, j, n] = min(i, j)*(n + 1) - i*j.at n=5A362679