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 1-8 of 8 results.

A045437 Primes congruent to 3 mod 7.

Original entry on oeis.org

3, 17, 31, 59, 73, 101, 157, 199, 227, 241, 269, 283, 311, 353, 367, 409, 479, 521, 563, 577, 619, 647, 661, 773, 787, 829, 857, 941, 983, 997, 1039, 1109, 1123, 1151, 1193, 1249, 1277, 1291, 1319, 1361, 1459, 1487, 1543, 1571, 1613, 1627, 1669, 1697, 1753
Offset: 1

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Author

Keywords

Comments

Also primes congruent to 3 mod 14.

Crossrefs

Primes arising in sequences A024903, A033868, A089033, A090614.
A090613 gives prime index.

Programs

Extensions

Extended by Ray Chandler, Dec 23 2003

A089033 Numbers n such that 7*n+3 is prime.

Original entry on oeis.org

0, 2, 4, 8, 10, 14, 22, 28, 32, 34, 38, 40, 44, 50, 52, 58, 68, 74, 80, 82, 88, 92, 94, 110, 112, 118, 122, 134, 140, 142, 148, 158, 160, 164, 170, 178, 182, 184, 188, 194, 208, 212, 220, 224, 230, 232, 238, 242, 250, 260, 268, 272, 278, 298, 304, 320, 334, 340
Offset: 1

Views

Author

Giovanni Teofilatto, Nov 12 2003

Keywords

References

  • M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988.
  • Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997.

Crossrefs

A045437 gives primes, A090613 gives prime index.

Programs

Formula

a(n) = A024903(n)-1 = A033868(n)-2 = A090614(n)*2.

Extensions

Corrected and extended by Ray Chandler, Nov 12 2003
Offset corrected by Arkadiusz Wesolowski, Aug 09 2011

A024903 Numbers k such that 7*k - 4 is prime.

Original entry on oeis.org

1, 3, 5, 9, 11, 15, 23, 29, 33, 35, 39, 41, 45, 51, 53, 59, 69, 75, 81, 83, 89, 93, 95, 111, 113, 119, 123, 135, 141, 143, 149, 159, 161, 165, 171, 179, 183, 185, 189, 195, 209, 213, 221, 225, 231, 233, 239, 243, 251, 261, 269, 273, 279, 299, 305, 321, 335, 341
Offset: 1

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Author

Keywords

Crossrefs

Cf. A045437 (associated primes), A090613 (gives prime index).

Programs

Formula

a(n) = A033868(n-1)-1 = A089033(n-1)+1 = A090614(n-1)*2+1.

A090613 Numbers k such that the k-th prime is congruent to 3 mod 7.

Original entry on oeis.org

2, 7, 11, 17, 21, 26, 37, 46, 49, 53, 57, 61, 64, 71, 73, 80, 92, 98, 103, 106, 114, 118, 121, 137, 138, 145, 148, 160, 166, 168, 175, 186, 188, 190, 196, 204, 206, 210, 215, 218, 232, 236, 243, 248, 255, 258, 263, 265, 273, 281, 289, 292, 296, 316, 321, 334
Offset: 1

Views

Author

Ray Chandler, Dec 23 2003

Keywords

Comments

Also numbers k such that the k-th prime is congruent to 3 mod 14.
A045437 indexed by A000040.
The asymptotic density of this sequence is 1/6 (by Dirichlet's theorem). - Amiram Eldar, Mar 01 2021

Crossrefs

Programs

  • Mathematica
    Select[Range[350], Mod[Prime[#], 7] == 3 &] (* Amiram Eldar, Mar 01 2021 *)

Formula

a(n) = k such that A000040(k) = A045437(n).

Extensions

Offset corrected by Amiram Eldar, Mar 01 2021

A140444 Primes congruent to 1 (mod 14).

Original entry on oeis.org

29, 43, 71, 113, 127, 197, 211, 239, 281, 337, 379, 421, 449, 463, 491, 547, 617, 631, 659, 673, 701, 743, 757, 827, 883, 911, 953, 967, 1009, 1051, 1093, 1163, 1289, 1303, 1373, 1429, 1471, 1499, 1583, 1597, 1667, 1709, 1723, 1877, 1933, 2003, 2017, 2087
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jun 26 2008

Keywords

Comments

From Federico Provvedi, May 24 2018: (Start)
Also primes congruent to 1 (mod 7).
For every prime p > 2, primes congruent to 1 (mod p) are also congruent to 1 (mod 2*p).
Conjecture: The monic polynomial P(x) = (x+1)^7/x - 1/x = ((x+1)^7-1)/x is irreducible but factorizable over Galois field (mod a(n)) with exactly 6 distinct irreducible factors of degree 1. Examples:
P(x) == (5 + x) (6 + x) (7 + x) (10 + x) (14 + x) (23 + x) (mod 29)
P(x) == (3 + x) (9 + x) (23 + x) (28 + x) (33 + x) (40 + x) (mod 43)
P(x) == (24 + x) (27 + x) (35 + x) (40 + x) (42 + x) (52 + x) (mod 71)
P(x) == (5 + x) (8 + x) (65 + x) (84 + x) (86 + x) (98 + x) (mod 113)
... (End).
Primes in A131877. - Eric Chen, Jun 14 2018

Crossrefs

A090613 gives prime index.
Cf. A090614.
Cf. A131877.
Primes congruent to 1 (mod k): A000040 (k=1), A065091 (k=2), A002476 (k=3 and 6), A002144 (k=4), A030430 (k=5 and 10), this sequence (k=7 and 14), A007519 (k=8), A061237 (k=9 and 18), A141849 (k=11 and 22), A068228 (k=12), A268753 (k=13 and 26), A132230 (k=15 and 30), A094407 (k=16), A129484 (k=17 and 34), A141868 (k=19 and 38), A141881 (k=20), A124826 (k=21 and 42), A212374 (k=23 and 46), A107008 (k=24), A141927 (k=25 and 50), A141948 (k=27 and 54), A093359 (k=28), A141977 (k=29 and 58), A142005 (k=31 and 62), A133870 (k=32).

Programs

  • GAP
    Filtered(Filtered([1..2300],n->n mod 14=1),IsPrime); # Muniru A Asiru, Jun 27 2018
  • Magma
    [p: p in PrimesUpTo(3000)|p mod 14 in {1}]; // Vincenzo Librandi, Dec 18 2010
    
  • Maple
    select(isprime,select(n->modp(n,14)=1,[$1..2300])); # Muniru A Asiru, Jun 27 2018
  • Mathematica
    Select[Prime[Range[500]], Mod[#, 14] == 1 &]  (* Harvey P. Dale, Mar 21 2011 *)
  • PARI
    is(n)=isprime(n) && n%14==1 \\ Charles R Greathouse IV, Jul 02 2016
    

Formula

a(n) ~ 6n log n. - Charles R Greathouse IV, Jul 02 2016

Extensions

Simpler definition from N. J. A. Sloane, Jul 11 2008

A033868 Numbers n such that 7*n-11 is prime.

Original entry on oeis.org

2, 4, 6, 10, 12, 16, 24, 30, 34, 36, 40, 42, 46, 52, 54, 60, 70, 76, 82, 84, 90, 94, 96, 112, 114, 120, 124, 136, 142, 144, 150, 160, 162, 166, 172, 180, 184, 186, 190, 196, 210, 214, 222, 226, 232, 234, 240, 244, 252, 262, 270, 274, 280, 300, 306, 322, 336, 342
Offset: 1

Views

Author

Giovanni Teofilatto, Dec 01 2003

Keywords

References

  • M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988.
  • Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997.

Crossrefs

Cf. A045437 (associated primes), A090613 (gives prime index).

Programs

Formula

a(n) = A024903(n)+1 = A089033(n)+2 = A090614(n)*2+2.

Extensions

Extended by Ray Chandler, Dec 23 2003
Offset corrected by Arkadiusz Wesolowski, Aug 09 2011

A140442 Primes congruent to 9 mod 14.

Original entry on oeis.org

23, 37, 79, 107, 149, 163, 191, 233, 317, 331, 359, 373, 401, 443, 457, 499, 541, 569, 653, 709, 751, 821, 863, 877, 919, 947, 1031, 1087, 1129, 1171, 1213, 1283, 1297, 1367, 1381, 1409, 1423, 1451, 1493, 1549, 1619, 1759, 1787, 1801, 1871, 1913, 1997
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jun 26 2008

Keywords

Crossrefs

Primes arising in sequences A045437, A045458, A045471, A045473.
A090613 gives prime index.
Cf. A090614.

Programs

Formula

a(n) = A045392(n+1) = A045383(n+2). - Zak Seidov, Mar 12 2014
a(n) ~ 6n log n. - Charles R Greathouse IV, Jul 03 2016

Extensions

1451 inserted by R. J. Mathar, Sep 13 2008

A153307 Numbers n such that 14*n+3 is not prime.

Original entry on oeis.org

3, 6, 8, 9, 10, 12, 13, 15, 18, 21, 23, 24, 27, 28, 30, 31, 32, 33, 35, 36, 38, 39, 42, 43, 45, 48, 49, 50, 51, 52, 53, 54, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 72, 73, 75, 76, 77, 78, 81, 83, 84, 86, 87, 88, 90
Offset: 1

Views

Author

Vincenzo Librandi, Dec 23 2008

Keywords

Examples

			Distribution of the terms in the following triangular array:
*;
*,*;
*,*,*;
*,3,*,*;
*,*,*,*,*;
*,*,*,*,10,*;
3,*,*,*,*,*,*;
*,*,*,*,*,*,18,*;
*,*,*,12,*,*,*,*,*;
*,*,*,*,*,*,*,*,*,*;
*,8,*,*,*,*,*,*,31,*,*;
*,*,*,*,*,23,*,*,*,*,*;
*,*,*,*,21,*,*,*,*,*,*,48,*;etc.
where * marks the non-integer values of (2*h*k + k + h - 1)/7 with h >= k >= 1. - _Vincenzo Librandi_, Jan 17 2013
		

Crossrefs

Programs

  • Magma
    [n: n in [0..150] | not IsPrime(14*n + 3)]; // Vincenzo Librandi, Jan 12 2013
  • Mathematica
    Select[Range[0, 200], !PrimeQ[14*# + 3]&] (* Vincenzo Librandi, Jan 12 2013 *)
Showing 1-8 of 8 results.