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.

A292618 The first prime of 8 consecutive primes a, b, c, d, e, f, g, h such that a + g = c + e and b + h = d + f.

Original entry on oeis.org

359, 389, 839, 853, 937, 1019, 2213, 2221, 2237, 2593, 3019, 3821, 3823, 4111, 4231, 4801, 5407, 5839, 6997, 12241, 13499, 14741, 15473, 25603, 25771, 25793, 26393, 28597, 29297, 30839, 31147, 31543, 35051, 40487, 45281, 47933, 50023, 51827, 55061, 55441, 60343
Offset: 1

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Author

Seiichi Manyama, Sep 20 2017

Keywords

Comments

In this condition, we can draw the following graphic whose sides are primes.
c
*------*
| |
d| |b
e | *---*
*------------* | a
| |
| |
| |
f| |h
| |
| g |
*---------------*
Dickson's conjecture implies that there are infinitely many prime octuplets of forms such as x, x+4, x+10, x+12, x+18, x+22, x+28, x+30, and thus infinitely many members of the sequence. - Robert Israel, Sep 20 2017

Examples

			If a = 359, b, c, d, e, f, g, h = 367, 373, 379, 383, 389, 397, 401.
		

Programs

  • Maple
    Primes:= select(isprime, [2,seq(i,i=3..10^5,2)]):
    Primes[select(i -> Primes[i]+Primes[i+6] = Primes[i+2]+Primes[i+4] and Primes[i+1]+Primes[i+7]=Primes[i+3]+Primes[i+5], [$1..nops(Primes)-7])];
    # Robert Israel, Sep 20 2017
  • PARI
    forprime(p=1, 61000, my(v=primes([p, nextprime(nextprime(nextprime(nextprime(nextprime(nextprime(nextprime(p+1)+1)+1)+1)+1)+1)+1)])); if(v[1]+v[7]==v[3]+v[5] && v[2]+v[8]==v[4]+v[6], print1(p, ", "))) \\ Felix Fröhlich, Sep 20 2017