The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A192267 Anti-deficient numbers. 5
 1, 2, 3, 4, 6, 9, 16, 19, 24, 26, 29, 34, 36, 44, 51, 54, 61, 64, 69, 79, 89, 96, 106, 114, 131, 134, 139, 141, 146, 156, 159, 166, 169, 174, 191, 194, 201, 209, 211, 216, 219, 224, 226, 236, 239, 244, 246, 251, 254, 261, 271, 274, 289, 296, 299, 309, 316 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS An anti-deficient number is a number n for which sigma*(n) < n, where sigma*(n) is the sum of the anti-divisors of n. Like A005100 but using anti-divisors. There are only 22 anti-deficient numbers less than 100, 159 less than 1000 and 1547 less than 10000. From an empirical observation it seems that the anti-deficient are approximately less than 18% of the anti-abundant. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..5000 from Paolo P. Lava) FORMULA A000027 = A073930 UNION {this set} UNION A192268. EXAMPLE 24 is anti-deficient because its anti-divisors are 7, 16 and their sum is 23 < 24. MAPLE isA192267 := proc(n) A066417(n) < n ; end proc: for n from 1 to 500 do if isA192267(n) then printf("%d, ", n); end if; end do: # R. J. Mathar, Jul 04 2011 MATHEMATICA antiDefQ[n_] := Total[Cases[Range[2, n - 1], _?(Abs[Mod[n, #] - #/2] < 1 &)]] < n; Select[Range[300], antiDefQ] (* Amiram Eldar, Jan 13 2022 after Michael De Vlieger at A066417 *) CROSSREFS Cf. A066417, A005100, A066272, A192268. Sequence in context: A268710 A223900 A326020 * A331022 A256774 A213682 Adjacent sequences: A192264 A192265 A192266 * A192268 A192269 A192270 KEYWORD nonn,easy AUTHOR Paolo P. Lava, Jun 28 2011 EXTENSIONS Edited by Ray Chandler, Dec 05 2011 STATUS approved

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

Last modified December 7 13:02 EST 2022. Contains 358656 sequences. (Running on oeis4.)