This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A058197 Where d(m) (number of divisors, A000005) rises by at least n. 4
 1, 5, 11, 11, 23, 23, 47, 47, 59, 59, 119, 119, 167, 167, 179, 179, 239, 239, 359, 359, 359, 359, 719, 719, 719, 719, 719, 719, 839, 839, 1259, 1259, 1259, 1259, 1679, 1679, 2519, 2519, 2519, 2519, 2519, 2519, 2519, 2519, 3359, 3359, 5039, 5039, 5039, 5039 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, 1996, Section II.1.3.a. LINKS T. D. Noe, Table of n, a(n) for n = 1..1004 FORMULA A051950(a(n) + 1) <= n. - Reinhard Zumkeller, Feb 04 2013 EXAMPLE d(11)=2, d(12)=6 gives first jump of >= 3, so a(3)=a(4)=11. MATHEMATICA d[m_] := d[m] = DivisorSigma[0, m]; td = Table[d[m] - d[m-1], {m, 2, 6000}]; a[n_] := Position[td, j_ /; j >= n, 1][[1, 1]]; Table[a[n], {n, Max[td]}] (* Jean-François Alcover, Nov 02 2011 *) With[{d=Differences[DivisorSigma[0, Range[5100]]]}, Flatten[Table[ Position[ d, _?(#>=n&), {1}, 1], {n, 50}]]] (* Harvey P. Dale, Oct 02 2015 *) PROG (Haskell) import Data.List (findIndex) import Data.Maybe (fromJust) a058197 n = (+ 1) \$ fromJust \$ findIndex (n <=) \$ tail a051950_list -- Reinhard Zumkeller, Feb 04 2013 CROSSREFS Equals A058198(n) - 1. Cf. A058199. Sequence in context: A060846 A113002 A179618 * A289464 A289580 A126243 Adjacent sequences:  A058194 A058195 A058196 * A058198 A058199 A058200 KEYWORD nonn,nice,easy AUTHOR N. J. A. Sloane, Nov 28 2000 EXTENSIONS More terms from James A. Sellers, Nov 29 2000 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 December 8 04:46 EST 2019. Contains 329853 sequences. (Running on oeis4.)