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.

A099227 Primes of the form m^k+k, with m and k > 1.

Original entry on oeis.org

11, 37, 67, 83, 227, 443, 521, 1091, 1523, 2027, 3251, 4099, 6563, 6569, 9803, 10651, 11027, 12323, 13691, 15131, 17579, 21611, 29243, 32771, 32783, 47963, 50627, 56171, 59051, 62003, 65027, 74531, 88211, 91811, 95483, 103043, 119027, 123203
Offset: 1

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Author

T. D. Noe, Oct 06 2004

Keywords

Comments

It appears that primes of this form are much less common than primes of the form m^k-k (A099228).
As N increases, squares <= N outnumber all higher powers <= N by an increasingly wide margin, so the above observation is increasingly a consequence of the fact that primes of the form m^2 + 2 are less common than primes of the form m^2 - 2. Among numbers of these two forms, multiples of 3 make up 2/3 of the former, but none of the latter. - Jon E. Schoenfield, Jun 05 2021

Crossrefs

Cf. A099225 (numbers of the form m^k+k, with m and k > 1), A093324 (least k such that n^k+k is prime).
Cf. A099228.

Programs

  • Mathematica
    nLim=200000; lst={}; Do[k=2; While[n=m^k+k; n<=nLim, AppendTo[lst, n]; k++ ], {m, 2, Sqrt[nLim]}]; Select[Union[lst], PrimeQ]
  • PARI
    list(lim)=my(v=List()); for(e=2,logint(lim\=1,2), forstep(n=3-e%2,sqrtnint(lim-e,e),2, my(t=n^e+e); if(isprime(t), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Jun 23 2023

A247336 Numbers of the form m^k - k - 1 with k > 0 and m > 1.

Original entry on oeis.org

0, 1, 4, 6, 11, 13, 22, 23, 26, 33, 46, 57, 60, 61, 76, 78, 97, 118, 120, 121, 141, 166, 193, 212, 222, 237, 247, 251, 253, 286, 321, 339, 358, 397, 438, 481, 502, 508, 526, 573, 620, 622, 673, 722, 725, 726, 781, 838, 897, 958, 996, 1013, 1018, 1021, 1086, 1153
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Sep 13 2014

Keywords

Comments

Primes in a(n): 11, 13, 23, 61, 97, 193, 251, 397, 673, 1013, 1021, 1153, ...

Examples

			0 is in this sequence because 2^1 - 1 - 1 = 0,
1 is in this sequence because 2^2 - 2 - 1 = 1.
		

Crossrefs

Formula

a(n + 1) = A057897(n) - 1.

A344990 Primes of the form m^k +- k, with m,k > 1.

Original entry on oeis.org

2, 5, 7, 11, 23, 37, 47, 61, 67, 79, 83, 167, 223, 227, 359, 439, 443, 503, 509, 521, 727, 839, 997, 1019, 1087, 1091, 1223, 1367, 1523, 1847, 2027, 2207, 2399, 2741, 3023, 3251, 3719, 3967, 4093, 4099, 4759, 5039, 5623, 5927, 6553, 6563, 6569, 7919, 8179
Offset: 1

Views

Author

Luke Voyles, Jun 05 2021

Keywords

Examples

			    2 =  2^2 - 2,
    5 =  2^3 - 3,
    7 =  3^2 - 2,
   11 =  3^2 + 2,
   23 =  5^2 - 2,
   37 =  2^5 + 5,
   47 =  7^2 - 2,
   61 =  4^3 - 3,
   67 =  4^3 + 3,
   79 =  9^2 - 2,
   83 =  9^2 + 2,
  167 = 13^2 - 2,
  223 = 15^2 - 2,
  227 = 15^2 + 2,
  359 = 19^2 - 2,
  439 = 21^2 - 2,
  443 = 21^2 + 2,
  503 =  2^9 - 9,
  509 =  8^3 - 3,
  521 =  2^9 + 9,
  ...
		

Crossrefs

Union of A099227 and A099228.
Showing 1-3 of 3 results.