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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A357697 Odd cubefree abundant numbers. 2
 1575, 2205, 3465, 4095, 5355, 5775, 5985, 6435, 6825, 7245, 8085, 8415, 8925, 9135, 9555, 9765, 11025, 11655, 12705, 12915, 13545, 14805, 15015, 16695, 17325, 18585, 19215, 19635, 20475, 21105, 21945, 22365, 22995, 23205, 24255, 24885, 25935, 26145, 26565, 26775 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First differs from A333950 at n = 1258. Terms that are not in A333950 include 8564325, 8565795, 8567325, ... and terms of A333950 that are not here include 1126125, 2096325, 2207205, ... . The numbers of terms not exceeding 10^k, for k = 4, 5, ..., are 16, 125, 1127, 11734, 116911, 1162781, 11638566, 116342286, ... . Apparently, the asymptotic density of this sequence exists and equals 0.00116... . LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 1575 = 3^2 * 5^2 * 7 is a term since it is odd and cubefree and sigma(1575) = 3224 > 2*1575. MATHEMATICA f[p_, e_] := (p^(e+1)-1)/(p-1); q[1] = 0; q[n_] := AllTrue[(fct = FactorInteger[n])[[;; , 2]], # < 3 &] && Times @@ f @@@ fct > 2*n; Select[Range[1, 30000, 2], q] PROG (PARI) is(n) = {my(f); if(n%2 == 0, return(0)); f = factor(n); (n==1 || vecmax(f[, 2]) < 3) && sigma(f, -1) > 2}; CROSSREFS Intersection of A004709 and A005231. Intersection of A005408 and A357695. A112643 is a subsequence. Cf. A000203 (sigma), A333950. Sequence in context: A045291 A125014 A333950 * A248694 A075460 A203087 Adjacent sequences: A357694 A357695 A357696 * A357698 A357699 A357700 KEYWORD nonn AUTHOR Amiram Eldar, Oct 10 2022 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 September 25 05:13 EDT 2023. Contains 365582 sequences. (Running on oeis4.)