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A119240 Least odd number k such that sigma(k)/k >= n. 7
1, 945, 1018976683725, 1853070540093840001956842537745897243375 (list; graph; refs; listen; history; text; internal format)



These numbers are a subset of the oddly superabundant numbers, A119239. Laatsch mentions a(3). Pettigrew computes a(4) and a(5), the latter being a 123-digit number.

Pettigrew (link, Tableau 5, p. 21) gives a(5) as 3^6*5^4*7^3*11^2*13^2*17^2*19*...*277. - Jeppe Stig Nielsen, Jul 03 2017


Jeppe Stig Nielsen, Table of n, a(n) for n = 1..5

Richard Laatsch, Measuring the abundancy of integers, Mathematics Magazine 59 (2) (1986) 84-92.

Walter Nissen, Abundancy : Some Resources

Steve Pettigrew, Sur la distribution de nombres spéciaux consécutifs, M.Sc. Thesis, Univ. Laval, 2000.


Cf. A023199 (least number k such that sigma(k)/k >= n).

Sequence in context: A263889 A133353 A322252 * A257722 A093247 A248785

Adjacent sequences:  A119237 A119238 A119239 * A119241 A119242 A119243




T. D. Noe, May 09 2006



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Last modified December 5 06:52 EST 2021. Contains 349543 sequences. (Running on oeis4.)