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A097296 Numbers n such that A001055(n) divides n. 2
1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 17, 19, 20, 22, 23, 26, 27, 28, 29, 30, 31, 34, 36, 37, 38, 41, 43, 44, 46, 47, 48, 52, 53, 56, 58, 59, 61, 62, 67, 68, 70, 71, 73, 74, 76, 79, 82, 83, 86, 89, 92, 94, 97, 101, 103, 105, 106, 107, 109, 110, 113, 116, 118, 122, 124, 127, 130 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Florian Luca, Anirban Mukhopadhyay and Kotyada Srinivas, On the Oppenheim's "factorisatio numerorum" function

FORMULA

Luca et al. estimate the density of this sequence (see their Theorem 3).

MAPLE

g:= proc(n, k) option remember; `if`(n>k, 0, 1)+

      `if`(isprime(n), 0, add(`if`(d>k, 0, g(n/d, d)),

         d=numtheory[divisors](n) minus {1, n}))

    end:

a:= proc(n) option remember; local k;

      for k from 1+`if`(n=1, 0, a(n-1))

      while irem(k, g(k$2))>0 do od; k

    end:

seq(a(n), n=1..100);  # Alois P. Heinz, May 16 2014

MATHEMATICA

g[n_, k_] := g[n, k] = If[n > k, 0, 1] + If[PrimeQ[n], 0, Sum[If[d > k, 0, g[n/d, d]], {d, Divisors[n] // Most // Rest}]]; a[1] = 1; a[n_] := (For[k = 1 + If[n == 1, 0, a[n-1]], Mod[k, g[k, k]] > 0 , k++]; k); Table[a[n], {n, 1, 100}] (* Jean-Fran├žois Alcover, Oct 07 2014, after Alois P. Heinz *)

CROSSREFS

Sequence in context: A279455 A050687 A098908 * A131616 A175857 A173919

Adjacent sequences:  A097293 A097294 A097295 * A097297 A097298 A097299

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Jun 12 2009

STATUS

approved

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Last modified March 22 01:06 EDT 2019. Contains 321406 sequences. (Running on oeis4.)