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 1-10 of 26 results. Next

A145471 Primes p such that (5+p)/2 is prime.

Original entry on oeis.org

5, 17, 29, 41, 53, 89, 101, 113, 137, 173, 197, 257, 269, 293, 353, 389, 449, 461, 509, 521, 557, 617, 701, 761, 773, 797, 857, 881, 929, 953, 977, 1013, 1109, 1181, 1193, 1229, 1277, 1289, 1301, 1361, 1433, 1481, 1613, 1637, 1709, 1721, 1877, 1889, 1901
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 1 mod 4 and to 5 mod 12.

Crossrefs

Subsequence of A040117. - Zak Seidov, Feb 21 2016

Programs

  • Magma
    [p: p in PrimesInInterval(3,2000) | IsPrime((5+p) div 2)]; // Vincenzo Librandi, Feb 25 2016
  • Maple
    select(t -> isprime(t) and isprime((t+5)/2), [seq(i, i=5..1000, 12)]); # Robert Israel, Feb 24 2016
  • Mathematica
    aa = {}; k = 5; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[500]],PrimeQ[(5+#)/2]&]  (* Harvey P. Dale, Apr 23 2011 *)
  • PARI
    forprime(p=2,1e4,if(p%12!=5,next);if(isprime(p\2+3),print1(p", "))) \\ Charles R Greathouse IV, Jul 16 2011
    

Formula

a(n) = 2*A063909(n)-5. - Robert Israel, Feb 24 2016

A145480 Primes p such that (p+37)/2 is prime.

Original entry on oeis.org

37, 97, 109, 157, 181, 241, 277, 349, 409, 421, 577, 661, 709, 757, 829, 877, 937, 1009, 1117, 1201, 1249, 1381, 1429, 1609, 1621, 1669, 1777, 1801, 2029, 2089, 2137, 2221, 2269, 2389, 2437, 2521, 2557, 2617, 2857, 3049, 3061, 3121, 3181, 3217, 3301, 3361
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 1 mod 12

Crossrefs

Programs

  • Mathematica
    aa = {}; k = 37; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[500]],PrimeQ[(37+#)/2]&] (* Harvey P. Dale, Jun 23 2016 *)
  • PARI
    list(n)=my(t=1, p, i=1); while(i2&&isprime((37+p)/2), print(p,", "))) \\Anders Hellström, Jan 23 2017
    
  • PARI
    list(lim)=my(v=List()); forprime(p=3,lim, if(isprime((p+37)/2), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Jan 23 2017

Formula

a(n) >> n log^2 n. - Charles R Greathouse IV, Jan 23 2017

A145490 Numbers k such that 6k+19 is prime and absolute value of 12k+1 is also prime.

Original entry on oeis.org

-2, -1, 3, 8, 9, 13, 15, 20, 23, 29, 34, 35, 48, 55, 59, 63, 69, 73, 78, 84, 93, 100, 104, 115, 119, 134, 135, 139, 148, 150, 169, 174, 178, 185, 189, 199, 203, 210, 213, 218, 238, 254, 255, 260, 265, 268, 275, 280, 288, 289, 293, 294, 295, 308, 309, 335, 344
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Crossrefs

Programs

  • Maple
    with(numtheory): a:=proc(n) if(isprime(6*n+19) and isprime(abs(12*n+1)))then return n: fi: return NULL: end: seq(a(n),n=-2..350); # Nathaniel Johnston, Jul 26 2011

Formula

a(n) = (A145480(n-2)-1)/12 for n >= 3.

Extensions

Corrected by Arkadiusz Wesolowski, Jul 26 2011

A092110 Primes p such that 2p+3 and 2p-3 are both prime.

Original entry on oeis.org

5, 7, 13, 17, 43, 53, 67, 97, 113, 127, 137, 157, 167, 193, 223, 283, 487, 547, 563, 613, 617, 643, 647, 743, 773, 937, 1033, 1187, 1193, 1277, 1427, 1453, 1483, 1543, 1583, 1627, 1663, 1733, 1847, 2027, 2143, 2297, 2393, 2437, 2467, 2477, 2503, 2617, 2843
Offset: 1

Views

Author

Zak Seidov, Feb 21 2004

Keywords

Comments

Intersection of A023204 and A063908.
All numbers in this sequence end with 3 or 7 (except the first one, which is 5). See A136191 or A136192. - Carlos Alves, Dec 20 2007

Examples

			From _K. D. Bajpai_, Sep 08 2020: (Start)
7 is a term because 2*7 + 3 = 17 and 2*7 - 3 = 11 are both prime.
13 is a term because 2*13 + 3 = 29 and 2*13 - 3 = 23 are both prime.
(End)
		

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(10000)|IsPrime(2*p-3) and IsPrime(2*p+3)] // Vincenzo Librandi, Nov 16 2010
  • Maple
    select(p -> isprime(p) and isprime(2*p+3) and isprime(2*p-3), [seq(2*k+1, k=1..1000)]); # K. D. Bajpai, Sep 08 2020
  • Mathematica
    Select[Prime@Range@1000,PrimeQ[2#-3]&&PrimeQ[2#+3]&] (* Vladimir Joseph Stephan Orlovsky, Apr 25 2011 *)

A145475 Primes p such that (17+p)/2 is prime.

Original entry on oeis.org

5, 17, 29, 41, 89, 101, 149, 197, 257, 281, 317, 449, 461, 509, 521, 569, 617, 677, 701, 761, 821, 881, 941, 1097, 1109, 1181, 1217, 1277, 1289, 1301, 1601, 1637, 1697, 1709, 1877, 1889, 1949, 2081, 2309, 2357, 2417, 2441, 2549, 2621, 2729, 2801, 2837, 2861
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 5 mod 12.

Crossrefs

Programs

  • Mathematica
    aa = {}; k = 17; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[500]],PrimeQ[(17+#)/2]&] (* Harvey P. Dale, Jan 02 2013 *)

A145472 Primes p such that (p+7)/2 is prime.

Original entry on oeis.org

3, 7, 19, 31, 67, 79, 127, 139, 151, 199, 211, 271, 307, 379, 439, 547, 607, 619, 691, 727, 739, 751, 787, 811, 859, 907, 919, 967, 991, 1039, 1087, 1231, 1279, 1447, 1459, 1471, 1531, 1567, 1699, 1747, 1759, 1831, 1867, 1987, 2011, 2131, 2179, 2239, 2251
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 3 mod 4 and (with the exception of the first one) to 7 mod 12.

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(2500)| IsPrime((p + 7) div 2)]; // Vincenzo Librandi, Feb 04 2013
    
  • Mathematica
    aa = {}; k = 7; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[400]],PrimeQ[(#+7)/2]&] (* Harvey P. Dale, Jan 11 2020 *)
  • PARI
    list(n)=my(t=1, p, i=1); while(i2&&isprime((7+p)/2), print1(n, ", "))) \\Anders Hellström, Jan 23 2017
    
  • PARI
    list(lim)=my(v=List()); forprime(p=3,lim, if(isprime((p+7)/2), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Jan 23 2017

A145474 Primes p such that (13+p)/2 is prime.

Original entry on oeis.org

13, 61, 73, 109, 181, 193, 241, 313, 349, 373, 409, 433, 541, 601, 613, 661, 733, 829, 853, 1033, 1069, 1129, 1201, 1213, 1249, 1453, 1489, 1609, 1693, 1741, 1753, 1801, 1861, 2029, 2053, 2089, 2113, 2161, 2221, 2293, 2389, 2593, 2749, 2833, 2953, 3049
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 1 mod 12.

Crossrefs

Programs

  • Maple
    select(t -> isprime(t) and isprime((13+t)/2), [seq(12*k+1, k=1..100)]); # Robert Israel, Aug 05 2014
  • Mathematica
    aa = {}; k = 13; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
  • PARI
    forprime(p=3,10^4,if(isprime((13+p)/2),print1(p,", "))) \\ Derek Orr, Aug 05 2014

A145476 Primes p such that (19 + p)/2 is prime.

Original entry on oeis.org

3, 7, 19, 43, 67, 103, 127, 139, 199, 283, 307, 367, 379, 439, 463, 523, 547, 607, 643, 727, 739, 823, 859, 907, 1063, 1123, 1303, 1327, 1399, 1447, 1459, 1483, 1627, 1699, 1747, 1999, 2083, 2239, 2287, 2383, 2539, 2887, 3067, 3079, 3307, 3319, 3463, 3499
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 3 mod 4 and (with the exception of the first term) to 5 mod 12.

Crossrefs

Programs

  • Mathematica
    aa = {}; k = 19; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[500]],PrimeQ[(#+19)/2]&] (* Harvey P. Dale, Sep 06 2023 *)
  • PARI
    list(n)=my(t=1,p,i=1);while(i2&&bigomega((19+p)/2)==1,print(p))) \\ Anders Hellström, Jan 22 2017

A145477 Primes p such that (23 + p)/2 is prime.

Original entry on oeis.org

3, 11, 23, 59, 71, 83, 179, 191, 239, 251, 311, 359, 431, 443, 479, 491, 503, 563, 599, 683, 743, 839, 863, 911, 983, 1019, 1091, 1103, 1151, 1163, 1259, 1283, 1499, 1523, 1571, 1619, 1871, 1931, 2003, 2039, 2099, 2339, 2351, 2411, 2423, 2531, 2543, 2579
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 3 mod 4 and (with the exception of the first term) to 11 mod 12.

Crossrefs

Programs

  • Mathematica
    aa = {}; k = 23; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
    Select[Prime[Range[400]],PrimeQ[(23+#)/2]&] (* Harvey P. Dale, Jan 26 2024 *)
  • PARI
    list(n)=my(t=1, p, i=1); while(i2&&prime((23+p)/2), print1(p, ", "))) \\ Anders Hellström, Jan 23 2017

A145478 Primes p such that (29 + p)/2 is prime.

Original entry on oeis.org

5, 17, 29, 53, 89, 113, 137, 149, 173, 197, 233, 269, 317, 353, 449, 509, 557, 593, 677, 773, 809, 857, 929, 953, 977, 1013, 1097, 1109, 1277, 1289, 1373, 1409, 1493, 1613, 1697, 1733, 1877, 1913, 1997, 2069, 2153, 2273, 2297, 2333, 2357, 2417, 2549, 2609
Offset: 1

Views

Author

Artur Jasinski, Oct 11 2008

Keywords

Comments

All these primes are congruent to 5 mod 12.

Crossrefs

Programs

  • Mathematica
    aa = {}; k = 29; Do[If[PrimeQ[(k + Prime[n])/2], AppendTo[aa, Prime[n]]], {n, 1, 500}];aa
  • PARI
    first(n)=my(t=1, p, i=1); while(i2&&isprime((29+p)/2), print1(p,", "))) \\ Anders Hellström, Jan 22 2017
Showing 1-10 of 26 results. Next