This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A231548 Numbers n such that 2*n - 1 < sigma(n) - sigma(n-2). 3
 1680, 2520, 3360, 3780, 3960, 4200, 4680, 5040, 6300, 6720, 7560, 7920, 8820, 9240, 9360, 10080, 10800, 10920, 11340, 11760, 11880, 12600, 13440, 13860, 14040, 15120, 15840, 15960, 16380, 16800, 17280, 17640, 18480, 18900, 19800, 20160, 20520, 21000, 21420 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also numbers n such that antisigma(n) < antisigma(n-2), where antisigma(n) = A024816(n) = the sum of the non-divisors of n that are between 1 and n. Sequence contains anomalous increased frequency of values ending with digit 0. Conjecture: there are not numbers n such that antisigma(n) < antisigma(n-3). LINKS Jaroslav Krizek, Table of n, a(n) for n = 1..228, all terms < 10^5 EXAMPLE 1680 is in sequence because antisigma(1680) = 1406088 < antisigma(1678) = 1406161. CROSSREFS Cf. A024816, A213547 (numbers n such that antisigma(n) < antisigma(n-1)). Sequence in context: A258920 A268288 A175749 * A179693 A290704 A175340 Adjacent sequences:  A231545 A231546 A231547 * A231549 A231550 A231551 KEYWORD nonn AUTHOR Jaroslav Krizek, Nov 12 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 17 21:37 EDT 2019. Contains 328134 sequences. (Running on oeis4.)