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.

A127364 Primes in A126558.

Original entry on oeis.org

1693333, 14251277, 17306687, 18067739, 25852399, 29126567, 55781581, 62333321, 113347009, 173863769, 204308891, 211281809, 247612801, 256102939, 267030149, 267670129, 277108457, 291010691, 298502489, 337176617, 365570923, 370598051
Offset: 1

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Author

Klaus Brockhaus, Jan 11 2007

Keywords

Comments

Prime interprimes of fourth order.
Primes that are the arithmetic mean of two consecutive prime interprimes of third order; primes of the form (A126557(k)+A126557(k+1))/2.

Crossrefs

Cf. A006562 (balanced primes), A024675 (interprimes), A126554 (interprimes of second order), A126555 (prime interprimes of second order), A126556 (interprimes of third order), A126557 (prime interprimes of third order), A126558 (interprimes of fourth order).

Programs

  • PARI
    {m=400000000;a=0;g=0;e=0;p=2;q=3;r=5;while(r<=m,if((p+r)/2==q,if(a>0,b=(a+q)/2;if(isprime(b),if(g>0,h=(g+b)/2;if(isprime(h),if(e>0,f=(e+h)/2;if(isprime(f),print1(f,",")));e=h));g=b));a=q);p=q;q=r;r=nextprime(r+1))}