[seqfan] Definition of sigma(n) which are powers, A180162

[Richard Mathar]

http://oeis.org/classic/A180162 shows
510 = a(4) claiming it is the first N such that sigma(N)
is a 4th power. Why isn't this 217 with sigma(217) = 256?

Shouldn't the sequence start (with -1=unknown)
1, 2, 3, 7, 217, 21, 2667, 93, 217, 381, 651, -1, 2667, 8191, 11811, 24573

Associated question: should these be merged?

http://oeis.org/classic/?q=id:A180170|id:A063782