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A074849 4-infinitary perfect numbers: n such that 4-infinitary-sigma(n)=2*n. 3
6, 28, 36720, 222768, 12646368, 5154170112, 34725010231296 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Here 4-infinitary-sigma(a) means sum of 4-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 4-ary expansion everywhere that the corresponding r(i) has a digit b, then d is a 4-infinitary-divisor of n.

LINKS

Table of n, a(n) for n=0..6.

EXAMPLE

Factorizations: 2*3, 2^2*7, 2^4*3^3*5*17, 2^4*3^2*7*13*17, 2^5*3^4*7*17*41, 2^8*3^2*7*13^2*31*61, 2^12*3^5*7*11*41*43*257.

CROSSREFS

Sequence in context: A154895 A330163 A276493 * A189373 A156927 A178366

Adjacent sequences:  A074846 A074847 A074848 * A074850 A074851 A074852

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto, Sep 10 2002

STATUS

approved

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Last modified June 18 20:04 EDT 2021. Contains 345121 sequences. (Running on oeis4.)