78428

Appears in sequences

• a(1) = 1, a(n) = Sum_{k=1..n-1} Sum_{d|k} a(d).at n=16A014668
• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 20.at n=28A031698
• a(n) = concatenation of n^2 and n.at n=27A055436
• a(n) = 100*n^2 + n.at n=27A055438
• a(n) is the least x such that the cyclotomic polynomial values Phi(d,x) are prime for all d dividing n.at n=32A072942
• a(n) = 400*n^2 + 2*n.at n=13A158312
• a(n) = 784*n^2 + 28.at n=10A158659
• First index in A362061 where A001221(A362061(a(n))) = n.at n=6A362062