A087167 - OEIS

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A087167

Odd numbers such that sigma(n)-2n=6.

8925, 32445, 442365 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`If m is in this sequence and 5 doesn't divide m then m is an odd Weird number. There are no other terms up to 210^9. Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu) wrote: There are no terms between 210^9 and 6.5*10^9.` `a(4) > 10^12. - Donovan Johnson, Dec 08 2011`
	REFERENCES	`S. Benkoski, "Are All Weird Numbers Even?" Amer. Math. Monthly 79, 774, 1972.` `R. K. Guy, "Almost Perfect, Quasi-Perfect, Pseudoperfect, Harmonic, Weird, Multiperfect and Hyperperfect Numbers." B2 in Unsolved Problems in Number Theory, 2nd ed.New York:Springer- Verlag, pp. 45-53, 1994.` `C. Rivera, Puzzle 233, www.primepuzzles.net`
	LINKS	`Eric Weisstein's World of Mathematics, Weird Number`
	EXAMPLE	`a(1)=8925 because sigma(8925)=2*8925+6 and 8925 is the first odd number that sigma(n)-2n=6.`
	MATHEMATICA	`Do[If[OddQ[n] && DivisorSigma[1, n] - 2n == 6, Print[n]], {n, 2*10^9}]`
	CROSSREFS	`Cf. A077374, A005101, A005835.` `Sequence in context: A206235 A185321 A065235 * A180298 A172637 A172745` `Adjacent sequences: A087164 A087165 A087166 * A087168 A087169 A087170`
	KEYWORD	`hard,more,nonn,bref`
	AUTHOR	`Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Oct 19 2003`

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Last modified February 17 05:54 EST 2012. Contains 205985 sequences.