81770

Appears in sequences

• Numbers that are the sum of 2 nonzero squares in exactly 8 ways.at n=16A025291
• Numbers that are the sum of 2 nonzero squares in 7 or more ways.at n=17A025298
• Numbers that are the sum of 2 nonzero squares in 8 or more ways.at n=17A025299
• Numbers that are the sum of 2 distinct nonzero squares in exactly 8 ways.at n=16A025309
• Numbers that are the sum of 2 distinct nonzero squares in 7 or more ways.at n=17A025317
• Numbers that are the sum of 2 distinct nonzero squares in 8 or more ways.at n=17A025318
• Partial sums of sequence {1/(i^2+1): i=0..n} (denominators).at n=6A033468
• Number of self-avoiding polygons on the 2-dimensional square lattice with perimeter 2n with at most 4 horizontal edges in each vertical cross-section.at n=8A060379
• Numbers n such that sum of distinct primes dividing n is divisible by the largest prime dividing n. Also n has exactly 5 distinct prime factors and n is squarefree.at n=23A071144
• Smallest number having exactly n representations as sum of two squares of distinct primes.at n=8A088919
• Numbers k that are the hypotenuse of exactly 40 distinct integer-sided right triangles, i.e., k^2 can be written as a sum of two squares in 40 ways.at n=9A097282
• a(n) = 121*n^2 - n.at n=25A157960
• a(n) = 484*n^2 - 2*n.at n=12A158329
• a(n) = 676*n^2 - 26.at n=10A158639
• a(n) = lcm(f(1),f(2),...,f(n)) with f(x) = x^2+1.at n=5A193181
• Least number having n orderless representations as p^2 + q^2, where p and q are primes.at n=7A214511
• Erroneous version of A339784.at n=5A220835
• First occurrence of n in A225099, or -1 if n does not appear in A225099.at n=8A225100
• Numbers k such that sum(d|k, sigma(d)^2) is a multiple of k.at n=10A226563
• a(n) is the number of reducible monic quartic polynomials (x^4 + r*x^3 + s*x^2 + t*x + u) with integer coefficients bounded by naïve height n (abs(r), abs(s), abs(t), abs(u) <= n).at n=14A358399