A126558 - OEIS

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A126558

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

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

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

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

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

PROG

(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

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).

Sequence in context: A234034 A154531 A043592 * A339752 A216400 A014778

Adjacent sequences: A126555 A126556 A126557 * A126559 A126560 A126561

KEYWORD

nonn

AUTHOR

Artur Jasinski, Dec 27 2006

EXTENSIONS

Edited and extended by Klaus Brockhaus, Jan 11 2007

STATUS

approved