1,2

a(n)^2 = {1, 4, 9, 400, 10609, ...} are the perfect squares in A120329 and A121166. A120329 = {1, 4, 6, 9, 10, 12, 22, 45, 400, 417, 561, 620, ...} Nonprime integers n such that n divides A120492(n). A121166 = {1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 17, 19, 22, 23, 29, 31, ...} Integers n such that n divides A120492[n] = 1 + Sum[ Prime[k]^(n-1), {k,1,n}].

Cf. A120492, A120329, A121166.

Sequence in context: A007113 A066166 A052804 this_sequence A042441 A128977 A069323

Adjacent sequences: A125760 A125761 A125762 this_sequence A125764 A125765 A125766

hard,more,nonn

Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 03 2007