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.

A022548 Initial members of prime nonuplets (p, p+4, p+10, p+12, p+18, p+22, p+24, p+28, p+30).

Original entry on oeis.org

88789, 855709, 74266249, 964669609, 1422475909, 2117861719, 2558211559, 2873599429, 5766036949, 6568530949, 8076004609, 9853497739, 16394542249, 21171795079, 21956291869, 22741837819, 26486447149, 27254489389
Offset: 1

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All terms are congruent to 169 (modulo 210). - Matt C. Anderson, May 28 2015

Crossrefs

Programs

  • Maple
    a := 1; for b to 25 do a := a*ithprime(b) end do; a;
    # so ‘a’ is the product of the primes 2 through 97
    composite_small := proc (n::integer)
    description "determine if n has a prime factor less than 100";
    if igcd(2305567963945518424753102147331756070, n) = 1 then return false else return true end if
    end proc;
    # my technique involves isprime(m*n+o+p)
    # with Multiplier, Number, Offset, and Pattern
    p := [0, 4, 10, 12, 18, 22, 24, 28, 30];
    o := [2059, 6679, 7519, 8989, 10249, 12139, 14449, 14869, 15919, 17179, 20539, 21379, 24109, 25999, 28729];
    with(ArrayTools);
    os := Size(o, 2);
    ps := Size(p, 2);
    m := 30030;
    loopstop := 10^11;
    loopstart := 0;
    for n from loopstart to loopstop do
    for a to os do
    counter := 0; wc := 0; wd := 0;
    while `and`(wd > -10, wd < ps) do
    wd := wd+1;
    if composite_small(m*n+o[a]+p[wd]) = false then wd := wd+1 else wd := -10 end if;
    end do;
    if wd >= 9 then
    while `and`(counter >= 0, wc < ps) do
    wc := wc+1;
    if isprime(m*n+o[a]+p[wc]) then counter := counter+1 else counter := -1 end if;
    end do;
    end if;
    if counter = ps then print(m*n+o[a]) end if;
    end do;
    end do;
    # Matt C. Anderson, Feb 13 2014
  • Mathematica
    Select[Prime[Range[2 10^6]], Union[PrimeQ[# + {4, 10, 12, 18, 22, 24, 28, 30}]] == {True} &] (* Vincenzo Librandi, Sep 30 2015 *)
  • PARI
    forprime(p=2, 10^30, if (isprime(p+4) && isprime(p+10) && isprime(p+12) && isprime(p+18) && isprime(p+22) && isprime(p+24) && isprime(p+28) && isprime(p+30), print1(p", "))) \\ Altug Alkan, Sep 30 2015
  • Perl
    use ntheory ":all"; say for sieve_prime_cluster(1,1e11, 4,10,12,18,22,24,28,30); # Dana Jacobsen, Sep 30 2015