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 1-4 of 4 results.

A078584 a(n) = prime(2n) - prime(2n-1).

Original entry on oeis.org

1, 2, 2, 2, 6, 6, 2, 6, 2, 4, 6, 6, 4, 4, 4, 4, 2, 2, 6, 6, 2, 2, 2, 12, 2, 6, 10, 6, 2, 4, 10, 4, 4, 6, 2, 6, 6, 4, 8, 8, 2, 2, 4, 8, 2, 12, 4, 4, 12, 18, 10, 6, 6, 6, 2, 6, 2, 10, 4, 6, 12, 6, 10, 10, 6, 4, 6, 8, 14, 12, 10, 4, 10, 4, 4, 4, 4, 4, 10, 4, 6, 4, 6, 6, 4, 2, 2, 10, 10, 6, 4, 4, 6, 6, 22, 10
Offset: 1

Views

Author

Robert G. Wilson v, Nov 30 2002

Keywords

Comments

First differences of A077133. Bisection of A001223.
Partition the primes in pairs starting with 5: (5, 7), (11, 13), (17, 19), (23, 29), (31, 37), (41, 43), (47, 53). Sequence gives differences between pairs. - Zak Seidov, Oct 05 2003

Examples

			a(4)=6 as a_o(5)=58 - a_e(5)=71 is 13 and a_o(4)=35 - a_e(4)=42 is 7 and the difference is 6.
		

Crossrefs

Programs

  • Mathematica
    Table[ Prime[2n] - Prime[2n - 1], {n, 100}] (* Robert G. Wilson v, May 29 2004 *)

Extensions

Edited by N. J. A. Sloane, Sep 15 2008 at the suggestion of R. J. Mathar

A088680 a(n) = prime(2n+1) - prime(2n).

Original entry on oeis.org

2, 4, 4, 4, 2, 4, 4, 6, 6, 2, 4, 8, 2, 2, 14, 6, 10, 6, 4, 6, 10, 4, 12, 4, 4, 2, 6, 6, 6, 2, 14, 2, 14, 10, 4, 8, 6, 6, 4, 10, 10, 6, 6, 4, 4, 8, 8, 6, 2, 6, 6, 2, 10, 6, 6, 4, 12, 2, 6, 2, 4, 8, 8, 8, 6, 8, 4, 4, 10, 2, 2, 2, 14, 2, 14, 2, 20, 8, 8, 6, 14, 6, 8, 12, 6, 10, 6, 2, 2, 18, 2, 6, 8, 6, 2
Offset: 1

Views

Author

Zak Seidov, Oct 05 2003

Keywords

Comments

Partition the primes into pairs starting with 3: (3, 5), (7, 11), (13, 17), (19, 23), (29, 31), (37, 41), (43, 47). Sequence gives differences between pairs.
A bisection of A001223.

Crossrefs

Programs

  • Mathematica
    Table[Prime[2n + 1] - Prime[2n], {n, 100}] (* Robert G. Wilson v, May 29 2004 *)
    Differences/@Partition[Prime[Range[2,200]],2]//Flatten (* Harvey P. Dale, Sep 22 2019 *)

Formula

a(n) = A001223(2*n).

Extensions

Edited by Robert G. Wilson v, May 29 2004
Offset corrected. - R. J. Mathar, Feb 23 2017

A088684 Prime(3n+3)-prime(3n+1).

Original entry on oeis.org

6, 6, 8, 6, 8, 6, 10, 6, 6, 10, 12, 10, 8, 6, 24, 6, 12, 12, 10, 24, 6, 16, 10, 12, 14, 18, 12, 10, 6, 20, 12, 14, 16, 8, 16, 8, 6, 12, 12, 16, 18, 18, 10, 10, 18, 14, 6, 24, 6, 6, 24, 18, 12, 10, 14, 10, 12, 12, 8, 6, 12, 12, 12, 16, 20, 12, 18, 20, 8, 6, 14, 40, 26, 18, 10, 6, 22, 6
Offset: 1

Views

Author

Zak Seidov, Oct 05 2003

Keywords

Comments

Minimal difference is 6 (for 3-tuplet). Repeating 6 means successive 3-tuplets.

Crossrefs

Programs

  • Maple
    Primes:= select(isprime, [2,seq(i,i=3..10000)]):
    seq(Primes[3*n+3]-Primes[3*n+1],n=1..(nops(Primes)-3)/3); # Robert Israel, Dec 15 2019
  • Mathematica
    Last[#]-First[#]&/@Partition[Prime[Range[4,250]],3] (* Harvey P. Dale, Sep 06 2011 *)

Formula

Partition primes in triples starting with 7: {7, 11, 13}, {17, 19, 23}, {29, 31, 37}, {41, 43, 47}, {53, 59, 61}, {67, 71, 73}, {79, 83, 89}, {97, 101, 103}, {107, 109, 113}. Sequence gives differences between lesser and larger primes in triples.

A088682 a(n) = prime(3*n+1) - prime(3*n-1).

Original entry on oeis.org

4, 6, 10, 10, 10, 8, 8, 14, 6, 18, 8, 8, 10, 12, 6, 16, 10, 16, 8, 6, 18, 18, 12, 14, 10, 12, 12, 8, 14, 6, 12, 10, 20, 16, 8, 12, 12, 14, 6, 8, 10, 18, 14, 12, 12, 24, 12, 6, 18, 18, 6, 12, 12, 20, 12, 18, 8, 8, 12, 24, 6, 14, 28, 18, 12, 16, 8, 22, 6, 8, 6, 8, 12, 28, 6, 14, 8, 12, 6, 24
Offset: 1

Views

Author

Zak Seidov, Oct 05 2003

Keywords

Comments

Previous name was: Partition the primes in triples starting with 3: {3, 5, 7}, {11, 13, 17}, {19, 23, 29}, {31, 37, 41}, {43, 47, 53}, {59, 61, 67}, {71, 73, 79}, {83, 89, 97}, {101, 103, 107}. Sequence gives differences between smallest and largest prime in each triple.
Minimal difference is 6 (for 3-tuplet) except first triple. Repeating 6 means successive 3-tuplets, see A088683, A088684, ...

Crossrefs

Programs

  • Mathematica
    Table[Prime[3n+1]-Prime[3n-1],{n,80}] (* Harvey P. Dale, Jul 28 2020 *)
  • PARI
    a(n) = prime(3*n+1) - prime(3*n-1); \\ Michel Marcus, Oct 05 2013

Extensions

New name from Michel Marcus, Oct 05 2013
Showing 1-4 of 4 results.