159049domain: NAppears in sequences5-dimensional centered cube numbers.at n=9A008515a(n) = 1250*n^2 - 1800*n + 649.at n=12A154358p^2 + (p+2)^2 - 1 where (p,p+2) is the n-th twin prime pair.at n=18A184417a(n) = 9^n + 10^n.at n=5A221904Numbers that are sums of two coprime positive fifth powers.at n=31A228542