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 1-2 of 2 results.

A372085 Primes starting a sequence of 6 consecutive primes with gaps 2, 4, 8, 16, 32.

Original entry on oeis.org

6824897, 10132607, 12674657, 13699457, 14148047, 27353237, 43918997, 44152307, 50608007, 53944337, 60426257, 60825827, 61325057, 68721047, 68933717, 72069707, 78577817, 82108127, 82334297, 87020177, 88226777, 97013927, 102043757, 106053917, 122271557, 140859707, 146049047, 161788787, 162036227
Offset: 1

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Author

Zak Seidov and Robert Israel, Apr 17 2024

Keywords

Comments

First differs from A079015 at a(25) = 122271557.
All terms == 7 (mod 10).

Examples

			a(3) = 12674657 is a term because 12674657 is prime and the next five primes are 12674657 + 2 = 12674659, 12674659 + 4 = 12674663, 12674663 + 8 = 12674671, 12674671 + 16 = 12674687 and 12674687 + 32 = 12674719.
		

Crossrefs

Cf. A079015, A372248 (gaps 2,4,8,16).

Programs

  • Maple
    p:= 2: state:= 1: count:= 0: Res:= NULL:
    while count < 100 do
      q:= nextprime(p);
      if q - p = 2^state then
         state:= state+1;
         if state = 6 then
           count:= count+1; Res:= Res,q-62;
         fi;
      else state:= 1
      fi;
      p:= q;
    od:
    Res;

A372247 Lowest prime p in a ladder of 4 consecutive primes p, p+2, p+6, p+14.

Original entry on oeis.org

1997, 2237, 2267, 2657, 6197, 6827, 8087, 17027, 17387, 19427, 21017, 21377, 22277, 22637, 23057, 24107, 29567, 37307, 43397, 43787, 53087, 55337, 56807, 58907, 62297, 65537, 65837, 78887, 81017, 82007, 82217, 89597, 90017, 91367, 93887, 95087, 97547, 105527, 108287, 110567, 112247, 113357
Offset: 1

Views

Author

R. J. Mathar, Apr 24 2024

Keywords

Examples

			2267, 2269, 2273 and 2281 are consecutive primes with gaps of 2, 4 and 8, so 2267 is in the sequence.
		

Crossrefs

Subsequence of A022004. A372248 is a subsequence.

Programs

  • Mathematica
    First /@ Parallelize[
      Select[Table[NextPrime[Prime@i, Range@4], {i, 10^5}],
       Differences@# == {2, 4, 8} &]] (* Mikk Heidemaa, Apr 25 2024 *)
Showing 1-2 of 2 results.