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.

A363999 Numbers of the form |2^i - 3^j|, for i >= 1, j >= 1.

Original entry on oeis.org

1, 5, 7, 11, 13, 17, 19, 23, 25, 29, 37, 47, 49, 55, 61, 65, 73, 77, 79, 101, 115, 119, 125, 139, 175, 179, 211, 217, 227, 229, 235, 239, 241, 247, 253, 269, 295, 431, 473, 485, 503, 509, 601, 665, 697, 713, 721, 725, 727, 781, 943, 997, 1015, 1021, 1163
Offset: 1

Views

Author

Clark Kimberling, Jul 30 2023

Keywords

Crossrefs

A364001 Primes of the form |2^i - 3^j|, i >= 1, j >= 1.

Original entry on oeis.org

5, 7, 11, 13, 17, 19, 23, 29, 37, 47, 61, 73, 79, 101, 139, 179, 211, 227, 229, 239, 241, 269, 431, 503, 509, 601, 727, 997, 1021, 1163, 1319, 1931, 2039, 2179, 3299, 3853, 4093, 4513, 6529, 6553, 7949, 8111, 11491, 14197, 16141, 16381, 19427, 19681, 32687
Offset: 1

Views

Author

Clark Kimberling, Aug 09 2023

Keywords

Crossrefs

Programs

  • Mathematica
    z = 500;
    t = Table[Abs[2^i - 3^j], {i, 1, z}, {j, 1, z}];
    u = Sort[Flatten[t]];
    v = Union[u] ; (* A363999 *)
    w = (v - 1)/2 ;  (* A364000 *)
    Intersection[v, Prime[Range[200000]]]  (* this sequence *)

A363997 Position in A088732 of the n-th prime.

Original entry on oeis.org

1, 2, 3, 4, 6, 7, 9, 5, 10, 8, 12, 15, 16, 19, 14, 21, 11, 22, 24, 18, 27, 20, 30, 31, 17, 34, 36, 37, 40, 28, 42, 45, 49, 51, 13, 26, 52, 54, 55, 38, 57, 32, 64, 33, 44, 66, 23, 46, 69, 35, 70, 25, 50, 75, 76, 79, 41, 82, 56, 84, 29, 58, 87, 60, 90, 91, 48
Offset: 1

Views

Author

Clark Kimberling, Jul 11 2023

Keywords

Comments

Every positive integer occurs exactly once.

Examples

			a(7) = 5 because the 7th prime, 19, is the 5th term in A088732.
		

Crossrefs

Programs

  • Mathematica
    z= 200; t = Table[k = 1; While[p = n + k*(n + 1); ! PrimeQ[p], k++];
      p, {n, 0, z}];   (* A088732, after Frank M Jackson *)
    Flatten[Table[Position[t, Prime[n]], {n, 1, z}]]  (* this sequence *)
Showing 1-3 of 3 results.