130682

Appears in sequences

• Denominators of continued fraction convergents to sqrt(679).at n=8A042305
• Numbers k such that core(k) = ceiling(sqrt(k)) where core(k) is the squarefree part of k (the smallest integer such that k*core(k) is a square).at n=17A069187
• a(n) = n^2*(n^2+1).at n=19A071253
• Sum of two powers of 19.at n=12A073214
• a(0)=0, a(1)=1, a(2n)=19*a(n), a(2n+1)=a(2n)+1.at n=20A197353
• Numbers k such that core(k) is equal to the sum of the proper square divisors of k, where core(k) = A007913(k).at n=12A225882
• Numbers of the form p^2 * (p^2 + 1) where p is in A225856.at n=6A225892
• Primitive numbers that are the sum of the squares of two of their distinct divisors.at n=31A338485
• a(n) = n^2*sigma_2(n).at n=19A386745