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.

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A094897 If 4*n+1 is not prime and 4*n+3 is prime then a(n)=4*n+3, else a(n)=0.

Original entry on oeis.org

3, 0, 11, 0, 0, 23, 0, 0, 0, 0, 0, 47, 0, 0, 59, 0, 67, 71, 0, 79, 83, 0, 0, 0, 0, 0, 107, 0, 0, 0, 0, 127, 131, 0, 0, 0, 0, 0, 0, 0, 163, 167, 0, 0, 179, 0, 0, 191, 0, 0, 0, 0, 211, 0, 0, 223, 227, 0, 0, 239, 0, 0, 251, 0, 0, 263, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 307, 311, 0, 0, 0, 0, 331, 0
Offset: 0

Views

Author

Roger L. Bagula, Jun 14 2004

Keywords

Crossrefs

Programs

  • Magma
    [IsPrime(4*n+3) and not IsPrime(4*n+1) select 4*n+3 else 0:n in [0..85]]; // Marius A. Burtea, Nov 15 2019
  • Maple
    A094897 := proc(n)
        if not isprime(4*n+1) and isprime(4*n+3) then
            4*n+3;
        else
            0;
        end if;
    end proc:
    seq(A094897(n),n=0..86) ; # R. J. Mathar, Nov 15 2019
  • Mathematica
    a=Table[If[PrimeQ[4*n+1]==False&&PrimeQ[4*n+3]==True, 4*n+3, 0], {n, 0, 200}]

A126955 Numbers n such that 2n+1, 3n+2 and 4n+3 are primes.

Original entry on oeis.org

1, 5, 65, 89, 119, 215, 455, 755, 779, 965, 1175, 1349, 1409, 1469, 1679, 1745, 1769, 1889, 1955, 2009, 2105, 2435, 2519, 2525, 2585, 2639, 4685, 5045, 5165, 5735, 5915, 5969, 6725, 7415, 7469, 7895, 8045, 9065, 9365, 9449, 9659, 9779, 9959, 10379
Offset: 1

Views

Author

J. M. Bergot, Mar 19 2007

Keywords

Examples

			Take n = 89. Then 2*89 + 1 = 179, 3*89 + 2 = 269 and 4*89 + 3 = 359 are primes.
		

Crossrefs

Intersection of A005097, A024893, A095278. Cf. A126956.

Programs

  • Mathematica
    Select[Range[10500], PrimeQ[2# + 1] && PrimeQ[3# + 2] && PrimeQ[4# + 3] &] (* Ray Chandler, Mar 20 2007 *)
    Select[Range[11000],AllTrue[{2#+1,3#+2,4#+3},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jan 23 2017 *)

Extensions

Extended by Ray Chandler, Robert G. Wilson v and Stuart Clary, Mar 20 2007

A156287 Numbers k such that 4*k-5 is a prime number.

Original entry on oeis.org

2, 3, 4, 6, 7, 9, 12, 13, 16, 18, 19, 21, 22, 27, 28, 33, 34, 36, 39, 42, 43, 46, 49, 51, 54, 57, 58, 61, 64, 67, 69, 72, 78, 79, 84, 88, 91, 93, 96, 97, 106, 109, 111, 112, 117, 118, 121, 123, 124, 126, 127, 132, 138, 142, 144, 148, 151, 153, 156, 159, 162, 163, 166
Offset: 1

Views

Author

Vincenzo Librandi, Feb 07 2009

Keywords

Comments

Two more than the associated A095278, one more than the associated A005099. - R. J. Mathar, Jan 05 2011

Crossrefs

Programs

A023250 Primes that remain prime through 2 iterations of function f(x) = 4x + 3.

Original entry on oeis.org

2, 7, 11, 37, 67, 89, 109, 149, 179, 257, 439, 467, 571, 677, 691, 719, 929, 977, 1019, 1279, 1381, 1447, 1549, 1567, 1747, 1787, 1901, 1931, 2111, 2161, 2207, 2287, 2347, 2377, 2459, 2539, 2671, 2711, 2819, 3119, 3229, 3371, 3491, 3607, 3637, 3821, 3877
Offset: 1

Views

Author

Keywords

Comments

Primes p such that 4*p+3 and 16*p+15 are also primes. - Vincenzo Librandi, Aug 04 2010

Crossrefs

Subsequence of A095278.

Programs

  • Magma
    [n: n in [0..100000] | IsPrime(n) and IsPrime(4*n+3) and IsPrime(16*n+15)]; // Vincenzo Librandi, Aug 04 2010
  • Maple
    A023250:=n->`if`(isprime(n) and isprime(4*n+3) and isprime(16*n+15), n, NULL): seq(A023250(n), n=1..10^4); # Wesley Ivan Hurt, Feb 12 2017
  • Mathematica
    Select[Range@ 3900, Times @@ Boole@ PrimeQ@ NestList[4 # + 3 &, #, 2] > 0 &] (* Michael De Vlieger, Sep 13 2016 *)

A105134 Numbers n such that 16n+9 is prime.

Original entry on oeis.org

2, 4, 5, 8, 14, 17, 19, 25, 28, 32, 35, 37, 38, 47, 50, 53, 58, 59, 64, 65, 68, 70, 74, 80, 82, 89, 92, 100, 103, 107, 109, 112, 119, 124, 130, 133, 134, 142, 143, 148, 149, 152, 154, 157, 163, 164, 169, 170, 173, 178, 184, 185, 187, 190, 200, 203, 214, 215, 220, 224, 229
Offset: 1

Views

Author

N. J. A. Sloane, based on correspondence from Marco Matosic, Apr 11 2005

Keywords

Crossrefs

Programs

A105138 Numbers n such that 256n+129 is prime.

Original entry on oeis.org

2, 4, 5, 10, 13, 17, 19, 25, 28, 37, 38, 40, 44, 47, 52, 53, 59, 62, 70, 74, 77, 79, 82, 83, 103, 110, 115, 119, 124, 130, 137, 140, 149, 152, 158, 170, 173, 178, 179, 193, 200, 205, 208, 209, 212, 217, 230, 235, 238, 242, 247, 248, 257, 268, 269, 272, 275, 280, 283, 299, 307
Offset: 1

Views

Author

N. J. A. Sloane, based on correspondence from Marco Matosic, Apr 11 2005

Keywords

Crossrefs

Programs

A105139 Numbers k such that 512*k+257 is prime.

Original entry on oeis.org

0, 1, 6, 15, 18, 27, 28, 43, 45, 52, 60, 61, 70, 73, 78, 81, 85, 90, 96, 97, 111, 112, 117, 138, 147, 151, 153, 165, 172, 178, 187, 192, 196, 202, 208, 210, 211, 213, 216, 222, 228, 231, 235, 243, 250, 252, 253, 255, 262, 265, 270, 280, 291, 298, 301, 312, 325, 328, 330, 337
Offset: 1

Views

Author

N. J. A. Sloane, based on correspondence from Marco Matosic, Apr 11 2005

Keywords

Crossrefs

Programs

A106068 Primes p such that 3p + 4 and 4p + 3 are primes.

Original entry on oeis.org

5, 11, 19, 31, 41, 59, 89, 109, 151, 179, 181, 229, 241, 331, 349, 389, 439, 509, 521, 599, 661, 719, 769, 839, 881, 929, 1019, 1039, 1129, 1229, 1291, 1409, 1451, 1481, 1549, 1669, 1741, 1759, 1801, 1811, 2111, 2131, 2539, 2621, 2671, 2699, 2819, 2879
Offset: 1

Views

Author

Zak Seidov, May 07 2005

Keywords

Comments

Prime terms in A124855.

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(5000)|IsPrime(3*p+4) and IsPrime(4*p+3)] // Vincenzo Librandi, Jan 30 2011
    
  • Mathematica
    Select[Prime[Range[450]], PrimeQ[4#+3]&&PrimeQ[3#+4]&]
  • PARI
    isok(p) = isprime(p) && isprime(3*p+4) && isprime(4*p+3); \\ Michel Marcus, Oct 12 2018

Extensions

Extended by Ray Chandler, Mar 14 2007

A126330 Primes of the form 4p+3 where p is a prime.

Original entry on oeis.org

11, 23, 31, 47, 71, 79, 127, 151, 167, 191, 239, 271, 359, 431, 439, 599, 607, 631, 719, 727, 911, 919, 967, 1031, 1087, 1231, 1327, 1399, 1439, 1471, 1559, 1607, 1759, 1831, 1847, 1871, 1951, 1999, 2039, 2087, 2287, 2311, 2351, 2399, 2591, 2647, 2711, 2767
Offset: 1

Views

Author

J. M. Bergot, Mar 09 2007

Keywords

Crossrefs

For the primes p see A023213.

Programs

  • Maple
    select(p -> isprime(p) and isprime((p-3)/4), [seq(p,p=7..10000,4)]); # Robert Israel, Aug 08 2019
  • Mathematica
    Select[3 + 4Prime@Range[130], PrimeQ] (* Ray Chandler, Jun 29 2008 *)

Extensions

Checked and extended by N. J. A. Sloane, Mar 10 2007

A126956 Numbers n such that 3n+2, 4n+3 and 5n+4 are primes.

Original entry on oeis.org

5, 17, 77, 89, 119, 185, 257, 287, 395, 665, 755, 797, 929, 1175, 1259, 1337, 1379, 1445, 1469, 1769, 2057, 2105, 3125, 3419, 3437, 3629, 3815, 3989, 4079, 4157, 4175, 4217, 4367, 4445, 4847, 5045, 5375, 6089, 6137, 6167, 6359, 6419, 6485, 6725, 6887
Offset: 1

Views

Author

J. M. Bergot, Mar 19 2007

Keywords

Examples

			Take n = 185. Then 3*185 + 2 = 557, 4*185 + 3 = 743 and 5*185 + 4 = 929 are primes.
		

Crossrefs

Intersection of A024893, A095278, A024897. Cf. A126955.

Programs

  • Mathematica
    Select[Range[7000], PrimeQ[3# + 2] && PrimeQ[4# + 3] && PrimeQ[5# + 4] &] (* Ray Chandler, Mar 20 2007 *)
    Select[Range[7000],AllTrue[{3#+2,4#+3,5#+4},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 06 2019 *)

Extensions

Corrected and extended by Ray Chandler, Stuart Clary, Robert G. Wilson v and Zak Seidov, Mar 20 2007
Previous Showing 11-20 of 29 results. Next