28566

Appears in sequences

• Pairs of Pythagorean numbers differing by 6.at n=39A228875
• Upper Pythagorean twins.at n=19A228877
• Numbers for which the number of prime divisors counted with multiplicity and the sum of the distinct prime divisors are both perfect.at n=18A233563
• Triangle T, read by rows, where T(n,k) = Sum_{j=1..n-k-1} [T^j](n-1,k) with T(n+1,n) = 2*n+1 and T(n,n)=0 for n>=0, where T^j denotes the j-th matrix power of T.at n=49A243920
• Differences of the increasing arithmetic progression a^2+a, b^2+b, c^2+c, where b = 5*a+2, c = 7*a+3 and a >= 0.at n=34A260955
• a(n) = Sum_{i=1..n-1}(i^(n-2)) mod n^4.at n=22A284760
• a(n) is the number of exterior top arches (no covering arch) for semi-meanders in generation n+1 that are generated by semi-meanders with n top arches and floor(n/2) exterior top arches using the exterior arch splitting algorithm.at n=11A366415
• Numbers k such that (in base 10) the k-th composite is a substring of the k-th prime.at n=4A378491
• Triangle T(n,k) read by rows: T(n,k) = -binomial(n+1,k) + Sum_{i=0..k} Sum_{j=0..i+1} (i+1)^(n-i+j)*(-1)^(k-i)/(j!*(k-i)!) for 0 <= k <= n.at n=51A380179