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A090615 Smallest member of sociable quadruples. 11
1264460, 2115324, 2784580, 4938136, 7169104, 18048976, 18656380, 28158165, 46722700, 81128632, 174277820, 209524210, 330003580, 498215416, 1236402232, 1799281330, 2387776550, 2717495235, 2879697304, 3705771825, 4424606020 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

120 sociable numbers of order 4 are known as of Feb. 2003.

142 were known in 2007 (http://amicable.homepage.dk/knwnc4.htm).

201 are known in 2012.

210 were known in April 2013. - Michel Marcus, Nov 10 2013

REFERENCES

R. K. Guy and J. L. Selfridge, Interim report on aliquot series, pp. 557-580 of Proceedings Manitoba Conference on Numerical Mathematics. University of Manitoba, Winnipeg, Oct 1971.

LINKS

Table of n, a(n) for n=1..21.

K. Blankenagel, W. Borho, A vom Stein, New amicable four-cycles, Math Comp 72 (2003) vol. 244, 2071.

D. Moews, A list of currently known aliquot cycles of length greater than 2.

Eric Weisstein's World of Mathematics, Sociable Numbers

CROSSREFS

Cf. A003023, A003416, A052470.

Sequence in context: A250825 A292217 A072892 * A222975 A180624 A081430

Adjacent sequences: A090612 A090613 A090614 * A090616 A090617 A090618

KEYWORD

nonn

AUTHOR

Eric W. Weisstein, Dec 06 2003

STATUS

approved

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Last modified November 29 10:31 EST 2022. Contains 358424 sequences. (Running on oeis4.)