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.

A079544 Primes of the form x^2 + y^2 + 1, x>0, y>0.

Original entry on oeis.org

3, 11, 19, 41, 53, 59, 73, 83, 101, 107, 131, 137, 149, 163, 179, 181, 227, 233, 251, 293, 307, 347, 389, 401, 443, 467, 491, 521, 523, 563, 587, 593, 613, 641, 677, 739, 773, 809, 811, 821, 883
Offset: 1

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Author

N. J. A. Sloane, Jan 23 2003

Keywords

Comments

Sequence is known to be infinite due to a result of Linnik.

References

  • D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 11.

Crossrefs

Cf. A079545.

Programs

  • Mathematica
    iMax=7!; a=Floor[Sqrt[iMax]]; lst={}; Do[Do[p=x^2+y^2+1; If[PrimeQ@p&&p<=iMax,AppendTo[lst,p]],{y,1,a}],{x,1,a}]; Union[lst] (* Vladimir Joseph Stephan Orlovsky, Aug 11 2009 *)
  • PARI
    list(lim)=my(v=List(),t); lim\=1; for(x=1,sqrtint(lim-2), forstep(y=2-x%2,min(x,sqrtint(lim-x^2-1)), 2, if(isprime(t=x^2+y^2+1), listput(v,t)))); vecsort(Vec(v),,8) \\ Charles R Greathouse IV, Jun 13 2012