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 1-5 of 5 results.

A246842 Primes p such that p + m^2 is prime for all m in {2,4,6,8,10,12,14,16}.

Original entry on oeis.org

37, 163, 56893, 409333, 1483087, 1867783, 10101463, 18292957, 31284493, 52896517, 58048057, 157861663, 175933717, 180336193, 222640867, 258001837, 276739747, 349693117, 371305267, 445890307, 543764323, 613305067, 678551833, 748576753, 828497443
Offset: 1

Views

Author

Zak Seidov, Sep 05 2014

Keywords

Comments

Primes p such that p + m^2, m = 2,4,6,8,10,12,14,16,18 are all primes:
163, 409333, 1483087, 1867783, 222640867, 258001837, 371305267, 748576753, 828497443, 1235054137, ...
Primes p such that p + m^2, m = 2,4,6,8,10,12,14,16,18,20 are all primes:
163, 409333, 828497443, ...

Crossrefs

Programs

  • PARI
    s=[]; forprime(p=2, 10e9, forstep(i=2, 16, 2, if(!isprime(p+i^2), next(2))); s=concat(s, p)); s \\ Colin Barker, Sep 05 2014

Extensions

Typos in data and comments fixed by Colin Barker, Sep 05 2014

A247269 Primes p such that p + m^2 is prime for all m in {2,4,6,8,10,12,14,16,18}.

Original entry on oeis.org

163, 409333, 1483087, 1867783, 222640867, 258001837, 371305267, 748576753, 828497443, 1235054137, 2059599067, 5767711867, 5929920613, 8965599883, 9055004953, 9170160343, 9655686727, 9670115977, 9671300983, 10646399437, 12253792783, 12627473917, 19635778453
Offset: 1

Views

Author

Zak Seidov, Sep 11 2014

Keywords

Comments

All terms are == 1 mod 6, and == {7, 13} mod 30.
Subsequence of A246842.

Crossrefs

Programs

  • PARI
    forprime(p=1,10^12,c=0;for(i=1,9,if(ispseudoprime(p+(2*i)^2),c++);if(!ispseudoprime(p+(2*i)^2),break));if(c==9,print1(p,", "))) \\ Derek Orr, Sep 11 2014
    
  • PARI
    is(n)=my(t=n%5); if(t!=2 && t!=3, return(0)); forstep(i=4,18,2, if(!isprime(n+i^2),return(0))); isprime(n) && isprime(n+4)
    p=2; forprime(q=3,1e12, if(q-p==4 && is(p), print1(p", ")); p=q) \\ Charles R Greathouse IV, Sep 11 2014

A247273 Primes p such that p + m^2 is prime for all m in {2,4,6,8,10,12,14,16,18,20,22}.

Original entry on oeis.org

163, 409333, 9671300983, 186521536807, 376040154163, 459775038913, 485142116713, 773464440907, 916792710667, 982557050143, 1087801149583, 1213507492723, 1822896797857, 2131006835017, 3026318319523, 4617478214407, 5141744558017, 6552892412047, 6629618954863, 6787014897877, 7636453217677, 7788411508483, 8311114648153, 8547311473387, 8668135024957, 9206471763547
Offset: 1

Views

Author

Zak Seidov, Sep 11 2014

Keywords

Comments

All terms are == {7, 13} mod 30.
Subsequence of A145741.

Crossrefs

Programs

  • PARI
    forprime(p=1,10^12,c=0;for(i=1,11,if(ispseudoprime(p+(2*i)^2),c++));if(c==11,print1(p,", "))) \\ Derek Orr, Sep 11 2014

A247275 Primes p such that p + m^2 is prime for all m in {2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24}.

Original entry on oeis.org

163, 409333, 376040154163, 1822896797857, 9871431850597, 13491637509487, 19802478368863
Offset: 1

Views

Author

Zak Seidov, Sep 11 2014

Keywords

Comments

All terms are == {7, 13} mod 30.
Subsequence of A247273.

Crossrefs

Programs

  • PARI
    forprime(p=1, oo, c=0; for(i=1, 12, if(ispseudoprime(p+(2*i)^2), c++)); if(c==12, print1(p, ", "))) \\ Derek Orr, Sep 11 2014

A247276 Primes p such that p + m^2 is prime for all m in {2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26}.

Original entry on oeis.org

163, 409333, 13491637509487, 19802478368863
Offset: 1

Views

Author

Zak Seidov, Sep 11 2014

Keywords

Comments

All terms are == {7, 13} mod 30.
Subsequence of A247275.

Crossrefs

Programs

  • Mathematica
    Select[Prime[Range[35000]],AllTrue[#+{4,16,36,64,100,144,196,256,324,400,484,576,676},PrimeQ]&] (* The program generates the first two terms of the sequence. To generate a(3) and a(4), increase the Range constant to 67*10^10 but the program will take a very long time to run. *) (* Harvey P. Dale, Mar 05 2025 *)
  • PARI
    forprime(p=1, 10^12, c=0; for(i=1, 13, if(ispseudoprime(p+(2*i)^2), c++);if(!ispseudoprime(p+(2*i)^2),break)); if(c==13, print1(p, ", "))) \\ Derek Orr, Sep 11 2014
Showing 1-5 of 5 results.