31620

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= n/2.at n=18A047166
• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-1)/2.at n=18A047177
• Triangle read by rows: T(n,k) = number of labeled semigroups of order n with k idempotents.at n=11A058166
• Indices n such that the 3 X 3 matrix with components (row by row) prime(n+k), 0 <= k <= 8, has zero determinant.at n=34A117345
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x+84847)^2 = y^2.at n=20A201917
• Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and 2w+x+y>0.at n=20A211617
• Degrees of irreducible representations of orthogonal group O10+(2).at n=18A214472
• Degrees of irreducible representations of orthogonal group O10+(2).at n=19A214472
• Even numbers such that the sum of the even divisors and the sum of the odd divisors are a square or a cube.at n=24A263695
• Magic sums of 4 X 4 magic squares composed of odd squares.at n=10A271582
• First term of A175304 with a given prime signature.at n=32A282231
• a(n) = (n^2 - 3*n + 6)*binomial(n+2,3)/4.at n=15A301973
• Number of partitions of prime(n) containing a prime number of primes.at n=13A343753
• Number of partitions of n containing a prime number of primes and an arbitrary number of nonprimes.at n=43A344677
• Triangle read by rows: T(n, k) = Sum_{d=0..n-k} binomial(n, d)*StirlingS2(n-d, k)*8^(n-d-k), with 0 <= k <= n.at n=52A364071
• Expansion of e.g.f. exp( ((1+3*x)^(2/3) - 1)/2 ).at n=7A380261
• Primitive terms of A388036.at n=34A388037