A097464 5-infinitary perfect numbers: n such that 5-infinitary-sigma(n)=2*n.

6, 28, 496, 47520, 288288, 308474880

Offset

1,1

Comments

Here 5-infinitary-sigma(a) means sum of 5-infinitary-divisor of a. If n=Product p_i^r_i and d=Product p_i^s_i, each s_i has a digit a<=b in its 5-ary expansion everywhere that the corresponding r_i has a digit b, then d is a 5-infinitary-divisor of n.

Is it certain that 308474880 is the 6th term? M. F. Hasler, Nov 20 2010

Links

Table of n, a(n) for n=1..6.

Formula

{n: A097863(n) = 2*n}.

Example

Factorizations: 2*3, 2^2*7, 2^4*31, 2^5*3^3*5*11, 2^5*3^2*7*11*13, 2^10*3*5*7*19*151

Crossrefs

Cf. A074849.

Sequence in context: A000396 A152953 A066239 * A354072 A166998 A038182

Adjacent sequences: A097461 A097462 A097463 * A097465 A097466 A097467

Keyword

nonn

Author

Yasutoshi Kohmoto

Extensions

Missing a(4) inserted by R. J. Mathar, Nov 20 2010

Status

approved