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A076254 A list of six integers with property that for every 3 numbers a,b,c from the list axbxc is an integer, where axb=a*b/(a+b) and axbxc=a*b*c/(a*b+a*c+b*c). This is the so-called replus operation. 0
248971642920, 497943285840, 746914928760, 995886571680, 1493829857520, 1991773143360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1) is the least common multiple of every ab+ac+bc, where a,b,c=1,2,3,4,6,8.

REFERENCES

Zoltan Kovacs, Abacus 2001.5 (Hungarian periodical)

LINKS

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

FORMULA

a(n)=n*a(1) for n=1, 2, 3, 4 a(5)=6*a(1), a(6)=8*a(1)

EXAMPLE

a(1)*a(2)*a(3) = a(1)*2a(1)*3a(1)/(a(1)*2a(1) + a(1)*3a(1) + 2a(1)*3a(1)) = 6a(1)/11 is an integer because 11 | a(1).

CROSSREFS

Sequence in context: A204781 A288477 A268846 * A213689 A015432 A034618

Adjacent sequences:  A076251 A076252 A076253 * A076255 A076256 A076257

KEYWORD

fini,full,nonn

AUTHOR

Miklos Kristof, Nov 05 2002

STATUS

approved

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Last modified April 19 04:19 EDT 2019. Contains 322237 sequences. (Running on oeis4.)