1,1

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

D. Minoli, Issues in non-linear hyperperfect numbers, Math. Comp., 34 (1980), 639-645.

J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 177.

J. S. McCranie, A study of hyperperfect numbers, J. Int. Seqs. Vol. 3 (2000) #P00.1.3

Sequence in context: A054366 A143049 A164643 this_sequence A012858 A084539 A034124

Adjacent sequences: A007591 A007592 A007593 this_sequence A007595 A007596 A007597

nonn

N. J. A. Sloane (njas(AT)research.att.com).

Jud McCranie (j.mccranie(AT)comcast.net) reports that the following terms are known:

6,21,325,1950625,?,301,?,?,?,159841,10693,697,?,?,?,

69091933912976476978420033,?,1333,51301,?,?,

865004941741938633917612789573739286076451841,?,?,?,?,?

where the missing terms, if they exist, are > 10^11. The large terms for 16 and 22 are the smallest known (7/98).