23562

Appears in sequences

• a(n) = n*(n + 1)*(n^2 + n + 2)/4.at n=17A001621
• a(n) = Sum_{k=0..floor(n/2)} T(n,k) * T(n,k+1), with T given by A026009.at n=8A027288
• Coordination sequence for A_17 lattice.at n=2A035843
• Numbers n such that 35*2^n-1 is prime.at n=22A050543
• Largest possible z-value of an integer solution (x,y,z) to 4/n = 1/x + 1/y + 1/z satisfying 0 < x < y < z. The x and y components are in A075245 and A075246.at n=31A075247
• Numbers k such that the central binomial coefficient C(2k,k) is divisible by k^2.at n=36A121943
• Call (m,n) a "(-1)SSU amicable pair" if (-1)Sigma(m)*Sigma(m) = k*UnitaryPhi(m)*(m+n) and (-1)Sigma(n)*Sigma(n) = k*UnitaryPhi(n)*(m+n) for some integer k. Sequence gives values of m, assuming n <= m.at n=6A123728
• Number of rectangles in a pyramid built with squares. The squares counted in A092498 are excluded.at n=18A134507
• Number of ways for each of 2n (labeled) people in a circle to look at either a neighbor or the diametrally opposite person, such that no eye contact occurs.at n=5A141221
• a(n) = (4*n+1)*(4*n+2) = (4*n+2)!/(4*n)!.at n=38A157870
• E.g.f. satisfies: A(x) = 1+x + x^2*exp(x*A(x)).at n=7A162697
• Sequence of the "Natural Jewels": a natural jewel is a number that is totally enclosed by prime numbers in a version of Ulam Spiral.at n=17A172294
• Number of strings of numbers x(i=1..n) in 0..7 with sum i^2*x(i)^3 equal to n^2*343.at n=9A184316
• Left edge of the triangle in A033291.at n=41A192735
• a(n) = 2*binomial(7*n+2,n)/(7*n+2).at n=5A233832
• Numbers n such that for some m, A166133(m)=n, A166133(m+1)=n^2-1, in increasing order.at n=40A256407
• z-value of the lexicographically first solution (x,y,z) of 4/n = 1/x + 1/y + 1/z with 0 < x < y < z all integers, or 0 if there is no such solution. Corresponding x and y values are in A257839 and A257840.at n=33A257841
• Numbers that are both interprime and oblong.at n=38A263676
• Total number of nonzero vectors over all subspaces of an n-dimensional vector space over the field with two elements.at n=6A289383
• Analog of A085635, replacing "quadratic residue" (X^2) with "value of X^2+X".at n=35A290727