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.

A152293 Primes of the form : (p-n)/(n+1)=prime and (n+1)*p+n=prime. n=3.

Original entry on oeis.org

11, 31, 47, 151, 271, 359, 439, 599, 719, 1031, 1759, 1871, 2287, 2711, 2767, 2879, 3719, 3911, 4079, 5119, 5527, 5791, 6199, 6271, 6991, 7151, 7607, 7727, 8447, 8647, 8831, 9151, 9391, 9511, 9839, 10159, 10687, 10847, 11279, 12479, 12919, 13487
Offset: 1

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This is the general form : (p-n)/(n+1)=primeand(n+1)*p+n=prime; 'Safe' primes and'Sophie Germain' primes just one part of this general form; If n=1 then we got'Safe' primes and'Sophie Germain' primes.

Crossrefs

Programs

  • Mathematica
    lst={};n=3;Do[p=Prime[k];If[PrimeQ[(p-n)/(n+1)]&&PrimeQ[(n+1)*p+n],AppendTo[lst,p]],{k,7!}];lst
    Select[Prime[Range[1600]],AllTrue[{(#-3)/4,4#+3},PrimeQ]&] (* Harvey P. Dale, Aug 24 2025 *)

A152294 Primes of the form : (p-n)/(n+1)=prime and (n+1)*p+n=prime. n=4.

Original entry on oeis.org

29, 89, 419, 509, 659, 1259, 1289, 1319, 1949, 2099, 2309, 2339, 2609, 2939, 3989, 4049, 6089, 6599, 7559, 8609, 9239, 9539, 10709, 12659, 12899, 13469, 13499, 18119, 20399, 21089, 21269, 21419, 22469, 23369, 26669, 27539, 28559, 30059, 30449
Offset: 1

Views

Author

Keywords

Comments

This is the general form : (p-n)/(n+1)=primeand(n+1)*p+n=prime; 'Safe' primes and'Sophie Germain' primes just one part of this general form; If n=1 then we got'Safe' primes and'Sophie Germain' primes.

Crossrefs

Programs

  • Mathematica
    lst={};n=4;Do[p=Prime[k];If[PrimeQ[(p-n)/(n+1)]&&PrimeQ[(n+1)*p+n],AppendTo[lst,p]],{k,7!}];lst

A152295 Primes of the form : (p-n)/(n+1)=prime and (n+1)*p+n=prime. n=5.

Original entry on oeis.org

17, 71, 83, 107, 191, 227, 251, 263, 431, 443, 479, 503, 587, 827, 839, 911, 983, 1091, 1151, 1163, 1187, 1619, 1667, 1847, 1907, 2087, 2243, 2459, 2591, 3023, 3467, 4463, 4871, 4943, 5471, 5519, 5651, 5807, 5903, 6131, 6203, 6299, 6311, 6563, 6983, 7127
Offset: 1

Views

Author

Keywords

Comments

This is the general form : (p-n)/(n+1)=primeand(n+1)*p+n=prime; 'Safe' primes and'Sophie Germain' primes just one part of this general form; If n=1 then we got'Safe' primes and'Sophie Germain' primes.

Crossrefs

Programs

  • Mathematica
    lst={};n=5;Do[p=Prime[k];If[PrimeQ[(p-n)/(n+1)]&&PrimeQ[(n+1)*p+n],AppendTo[lst,p]],{k,7!}];lst
    Select[Prime[Range[1000]],AllTrue[{(#-5)/6,6#+5},PrimeQ]&] (* This program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 29 2014 *)

A152388 Primes p such that (p-n)/(n+1) and (n+1)*p+n are both prime, with n=127.

Original entry on oeis.org

6143, 11519, 23039, 205823, 253439, 345599, 417023, 463103, 752639, 1071359, 1474559, 1511423, 1753343, 1766399, 1903103, 2188799, 2271743, 2711039, 2741759, 2747903, 2813183, 2997503, 3032063, 3258623, 3371519, 3463679
Offset: 1

Views

Author

Keywords

Comments

This is the general form : (p-n)/(n+1)=primeand(n+1)*p+n=prime; 'Safe' primes and'Sophie Germain' primes just one part of this general form; If n=1 then we got'Safe' primes and'Sophie Germain' primes.

Crossrefs

Programs

  • Mathematica
    lst={};n=127;Do[p=Prime[k];If[PrimeQ[(p-n)/(n+1)]&&PrimeQ[(n+1)*p+n],AppendTo[lst,p]],{k,2*9!}];lst
    Select[Prime[Range[250000]],AllTrue[{(#-127)/128,128#+127},PrimeQ]&] (* Harvey P. Dale, Apr 30 2023 *)

Extensions

Definition clarified by Harvey P. Dale, Apr 30 2023
Showing 1-4 of 4 results.