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 1-2 of 2 results.

A242119 Primes modulo 18.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 1, 5, 11, 13, 1, 5, 7, 11, 17, 5, 7, 13, 17, 1, 7, 11, 17, 7, 11, 13, 17, 1, 5, 1, 5, 11, 13, 5, 7, 13, 1, 5, 11, 17, 1, 11, 13, 17, 1, 13, 7, 11, 13, 17, 5, 7, 17, 5, 11, 17, 1, 7, 11, 13, 5, 1, 5, 7, 11, 7, 13, 5, 7, 11, 17, 7, 13, 1, 5
Offset: 1

Views

Author

Vincenzo Librandi, May 05 2014

Keywords

Crossrefs

Cf. sequences of the type Primes mod k: A039701 (k=3), A039702 (k=4), A039703 (k=5), A039704 (k=6), A039705 (k=7), A039706 (k=8), A038194 (k=9), A007652 (k=10), A039709 (k=11), A039710 (k=12), A039711 (k=13), A039712 (k=14), A039713 (k=15), A039714 (k=16), A039715 (k=17), this sequence (k=18), A033633 (k=19), A242120(k=20), A242121 (k=21), A242122 (k=22), A229786 (k=23), A229787 (k=24), A242123 (k=25), A242124 (k=26), A242125 (k=27), A242126 (k=28), A242127 (k=29), A095959 (k=30), A110923 (k=100).

Programs

  • Magma
    [p mod(18): p in PrimesUpTo(500)];
    
  • Mathematica
    Mod[Prime[Range[100]], 18]
  • Sage
    [mod(p, 18) for p in primes(500)] # Bruno Berselli, May 05 2014

Formula

Sum_{i=1..n} a(i) ~ 9n. The derivation is the same as in the formula in A039715. - Jerzy R Borysowicz, Apr 27 2022

A248199 Initial primes of sets of 8 consecutive primes all different by modulo 30.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 47, 499, 673, 677, 769, 1277, 1279, 1327, 1697, 2357, 3163, 3907, 4057, 4133, 4909, 5479, 5669, 6047, 7283, 9349, 9533, 9539, 9547, 9923, 10667, 11149, 11159, 12277, 12841, 17167, 17431, 17443, 21101, 21379, 22549, 22567, 22993, 24181, 24337, 24659, 24671, 25219, 26161
Offset: 1

Views

Author

Zak Seidov, Oct 03 2014

Keywords

Examples

			47 is a term because 8 consecutive primes {47, 53, 59, 61, 67, 71, 73, 79} are congruent to {17, 23, 29, 1, 7, 11, 13, 19} mod 30; all distinct by modulo 30.
		

Crossrefs

Cf. A095959 (primes modulo 30).

Programs

  • PARI
    isok(n) = {v = []; for (i=0, 7, pm = prime(i+n) % 30; if (! vecsearch(v, pm), v = vecsort(concat(v, pm)), return (0));); return (1);}
    lista(nn) = {forprime(p=2, nn, if (isok(primepi(p)), print1(p, ", ")););} \\ Michel Marcus, Oct 06 2014
Showing 1-2 of 2 results.