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 1-3 of 3 results.

A126556 Arithmetic mean of two consecutive prime interprimes of second order: interprimes of third order.

Original entry on oeis.org

734, 2825, 5957, 10305, 13932, 15830, 18825, 25084, 30205, 32121, 34901, 40640, 47984, 70842, 102897, 120165, 125973, 130250, 138924, 145480, 148894, 154236, 161676, 167730, 174737, 180632, 183077, 191253, 210375, 224327, 232817, 246285
Offset: 1

Views

Author

Artur Jasinski, Dec 27 2006

Keywords

Comments

For primes in this sequence (prime interprimes of third order) see A126557.

Links

Crossrefs

Cf. A006562 (balanced primes), A024675 (interprimes), A126554 (interprimes of second order), A126555 (prime interprimes of second order).

Programs

  • PARI
    {m=250000;a=0;g=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,print1(h=(g+b)/2,","));g=b));a=q);p=q;q=r;r=nextprime(r+1))} \\ Klaus Brockhaus, Jan 11 2007

Formula

a(n) = (A126555(n)+A126555(n+1))/2.

Extensions

Edited by Klaus Brockhaus, Jan 11 2007

A126558 Arithmetic mean of two consecutive prime interprimes of third order: interprimes of fourth order.

Original entry on oeis.org

199532, 329070, 487630, 664345, 878455, 974874, 1030434, 1183684, 1329780, 1453746, 1550775, 1568843, 1573919, 1618431, 1693333, 1829142, 2087087, 2262462, 2348799, 2438192, 2811665, 3436775, 3900917, 4270580, 4830665
Offset: 1

Views

Author

Artur Jasinski, Dec 27 2006

Keywords

Comments

For primes in this sequence (prime interprimes of fourth order) see A127364.

Links

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).

Programs

  • PARI
    {m=5000000;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;print1(f,","));e=h));g=b));a=q);p=q;q=r;r=nextprime(r+1))} \\ Klaus Brockhaus, Jan 11 2007

Formula

a(n) = (A126557(n)+A126557(n+1))/2.

Extensions

Edited and extended by Klaus Brockhaus, Jan 11 2007

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

Views

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.

Links

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))}
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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