cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A333542 The primes missing from A333541.

Original entry on oeis.org

2, 11, 53, 59, 71, 73, 89, 97, 103, 107, 127, 131, 163, 173, 179, 181, 191, 193, 197, 223, 229, 233, 241, 251, 263, 271, 281, 293, 311, 331, 337, 347, 349, 359, 367, 383, 401, 419, 421, 431, 443, 449, 457, 461, 463, 467, 479, 487, 491, 509, 521, 523, 541, 547, 557, 563
Offset: 1

Views

Author

N. J. A. Sloane, Apr 20 2020

Keywords

Comments

These are the primes that are not record high values in A333537.

Examples

			We have A333541(k) = 7 for some k and the term after that A333541(k + 1) = 13. As 11 is a prime between 7 and 13, 11 is in the sequence. - _David A. Corneth_, Apr 21 2020
		

Crossrefs

Extensions

More terms from David A. Corneth, Apr 21 2020

A333537 Greatest prime factor of A332559.

Original entry on oeis.org

3, 3, 3, 2, 5, 3, 3, 3, 5, 5, 3, 3, 5, 5, 5, 3, 3, 3, 3, 3, 7, 5, 5, 5, 5, 7, 7, 7, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 5, 3, 3, 3, 3, 3, 3, 7, 7, 7, 7, 5, 5, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, 3, 3, 3, 5, 5, 5, 5, 5, 5, 5, 5, 7, 7, 7, 5, 5, 5, 5, 5, 5, 5, 3, 3, 3, 3, 5, 5, 13, 7, 7, 7, 7, 7, 7, 7, 3, 7, 7, 7, 7, 7, 7, 5
Offset: 1

Views

Author

N. J. A. Sloane, Apr 12 2020

Keywords

Comments

For rate of growth, see the Myers et al. link. - N. J. A. Sloane, Apr 30 2020

Crossrefs

Programs

  • Mathematica
    a[n_] := Module[{k, p = n}, For[k = 1, True, k++, p *= (n+k); If[Divisible[ p, n+k+1], Return[FactorInteger[n+k+1][[-1, 1]]]]]];
    Array[a, 1000] (* Jean-François Alcover, Aug 17 2020 *)

A333538 Indices of records in A333537.

Original entry on oeis.org

1, 5, 21, 91, 355, 456, 666, 2927, 4946, 6064, 6188, 6192, 13858, 14884, 39592, 54429, 77603, 87566, 210905, 245770, 422097, 585876, 908602, 976209, 1240768, 1340675, 1573890, 2589172, 4740893, 5168099, 8525972, 8646462, 10478354, 12636785, 17943798, 19524935
Offset: 1

Views

Author

N. J. A. Sloane, Apr 12 2020

Keywords

Comments

The first few primes that are not record values of A333537 are 2, 11, 53, 59, 71, 73, 89, 97, 103, 107 (see A333541, A333542). - Robert Israel, Apr 12 2020
a(72) > 5*10^9. - David A. Corneth, Apr 14 2020

Crossrefs

Programs

  • Maple
    f:= proc(n) local k, p;
      p:= n;
      for k from 1 do
        p:= p*(n+k);
        if (p/(n+k+1))::integer then return n+k+1 fi
      od
    end proc:
    R:= 1: g:= 3: count:= 1:
    for n from 2 while count < 20 do
      x:= max(numtheory:-factorset(f(n)));
      if x > g then count:= count+1; g:= x; R:= R, n;  fi
    od:
    R; # Robert Israel, Apr 12 2020
  • Mathematica
    f[n_] := Module[{k, p = n}, For[k = 1, True, k++, p *= (n+k); If[Divisible[ p, n + k + 1], Return[FactorInteger[n + k + 1][[-1, 1]]]]]];
    R = {1}; g = 3; count = 1;
    For[n = 2, count < 20, n++, x = f[n]; If[x > g, count++; g = x; AppendTo[R, n]]];
    R (* Jean-François Alcover, Aug 17 2020, after Robert Israel *)

Extensions

a(13)-a(20) from Robert Israel, Apr 12 2020
More terms from Jinyuan Wang, Apr 12 2020
Showing 1-3 of 3 results.