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 10 results.

A167134 Primes congruent to {2, 3, 5, 7} mod 11.

Original entry on oeis.org

2, 3, 5, 7, 13, 29, 47, 71, 73, 79, 101, 113, 137, 139, 157, 167, 179, 181, 211, 223, 227, 233, 269, 271, 277, 293, 311, 313, 337, 359, 379, 401, 409, 421, 431, 443, 467, 487, 491, 509, 541, 557, 563, 577, 599, 601, 607, 619, 641, 643, 673, 709, 733, 739, 751
Offset: 1

Views

Author

Klaus Brockhaus, Oct 28 2009

Keywords

Comments

Primes p such that p mod 11 is prime.
Primes of the form 11*n+r where n >= 0 and r is in {2, 3, 5, 7}.
2 and primes congruent to {3, 5, 7, 13} mod 22. - Chai Wah Wu, Apr 29 2025

Crossrefs

Cf. A003627, A045326, A003631, A045309, A045314, A042987, A078403, A042993, A167134, A167135, A167119: primes p such that p mod k is prime, for k = 3..13 resp.

Programs

  • Magma
    [ p: p in PrimesUpTo(760) | p mod 11 in {2, 3, 5, 7} ];
    [ p: p in PrimesUpTo(760) | exists(t){ n: n in [0..p div 11] | exists(u){ r: r in {2, 3, 5,7} | p eq (11*n+r) } } ];
  • Mathematica
    Select[Prime[Range[600]],MemberQ[{2, 3, 5, 7},Mod[#,11]]&] (* Vincenzo Librandi, Aug 05 2012 *)

A167135 Primes congruent to {2, 3, 5, 7, 11} mod 12.

Original entry on oeis.org

2, 3, 5, 7, 11, 17, 19, 23, 29, 31, 41, 43, 47, 53, 59, 67, 71, 79, 83, 89, 101, 103, 107, 113, 127, 131, 137, 139, 149, 151, 163, 167, 173, 179, 191, 197, 199, 211, 223, 227, 233, 239, 251, 257, 263, 269, 271, 281, 283, 293, 307, 311, 317, 331, 347, 353, 359
Offset: 1

Views

Author

Klaus Brockhaus, Oct 28 2009

Keywords

Comments

Primes p such that p mod 12 is prime.
Primes of the form 12*n+r where n >= 0 and r is in {2, 3, 5, 7, 11}.
Except for the prime 2, these are the primes that are encountered in the set of numbers {x, f(f(x))} where x is of the form 4k+3 with k>=0, and where f(x) is the 3x+1-problem function, and f(f(x)) the second iteration value. Indeed this sequence is the set union of 2 and A002145 (4k+3 primes) and A007528 (6k+5 primes), since f(f(4k+3))=6k+5. Equivalently one does not get any prime from A068228 (the complement of the present sequence). - Michel Marcus and Bill McEachen, May 07 2016

Crossrefs

Subsequences: A002145, A007528. Complement: A068228.
Cf. A003627, A045326, A003631, A045309, A045314, A042987, A078403, A042993, A167134, A167135, A167119: primes p such that p mod k is prime, for k = 3..13 resp.

Programs

  • Magma
    [ p: p in PrimesUpTo(760) | p mod 12 in {2, 3, 5, 7, 11} ];
    
  • Magma
    [ p: p in PrimesUpTo(760) | exists(t){ n: n in [0..p div 12] | exists(u){ r: r in {2, 3, 5,7, 11} | p eq (12*n+r) } } ];
  • Maple
    isA167135  := n -> isprime(n) and not modp(n, 12) != 1:
    select(isA167135, [$1..360]); # Peter Luschny, Mar 28 2018
  • Mathematica
    Select[Prime[Range[400]],MemberQ[{2,3, 5, 7, 11},Mod[#,12]]&] (* Vincenzo Librandi, Aug 05 2012 *)
    Select[Prime[Range[72]], Mod[#, 12] != 1 &] (* Peter Luschny, Mar 28 2018 *)

A201717 Primes of the form 3*m^2 - 5.

Original entry on oeis.org

7, 43, 103, 967, 1447, 1723, 2347, 3067, 3463, 4327, 6343, 6907, 9403, 11527, 13063, 21163, 23227, 28807, 32443, 33703, 44647, 47623, 52267, 65707, 71143, 74887, 80683, 88747, 90823, 99367, 110587, 137383, 142567, 150523, 175687
Offset: 1

Views

Author

Vincenzo Librandi, Dec 05 2011

Keywords

Comments

Primes p such that 3*(p+5) or (p+5)/3 is a square. - Vincenzo Librandi, Feb 16 2016

Crossrefs

Cf. A000040, A042993 (supersequence).
Cf. similar sequences: A089682, A201715, A201716, A201718, A201781.

Programs

  • Magma
    [a: n in [2..300] | IsPrime(a) where a is 3*n^2-5];
  • Mathematica
    Select[Table[3n^2-5,{n,2,1000}],PrimeQ]

A167119 Primes congruent to 2, 3, 5, 7 or 11 (mod 13).

Original entry on oeis.org

2, 3, 5, 7, 11, 29, 31, 37, 41, 59, 67, 83, 89, 107, 109, 137, 163, 167, 193, 197, 211, 223, 239, 241, 263, 271, 293, 317, 349, 353, 367, 379, 397, 401, 419, 421, 431, 449, 457, 479, 499, 509, 523, 557, 577, 587, 601, 613, 631, 653, 661, 683, 691, 709, 733, 739, 743, 757
Offset: 1

Views

Author

Keywords

Comments

Primes which have a remainder mod 13 that is prime.
Union of A141858, A100202, A102732, A140371 and A140373. - R. J. Mathar, Oct 29 2009

Examples

			11 mod 13 = 11, 29 mod 13 = 3, 31 mod 13 = 5, hence 11, 29 and 31 are in the sequence.
		

Crossrefs

Cf. A003627, A045326, A003631, A045309, A045314, A042987, A078403, A042993, A167134, A167135: primes p such that p mod k is prime, for k = 3..12 resp.

Programs

  • Magma
    [ p: p in PrimesUpTo(740) | p mod 13 in {2, 3, 5, 7, 11} ]; // Klaus Brockhaus, Oct 28 2009
  • Mathematica
    f[n_]:=PrimeQ[Mod[n,13]]; lst={};Do[p=Prime[n];If[f[p],AppendTo[lst,p]],{n,6,6!}];lst
    Select[Prime[Range[4000]],MemberQ[{2, 3, 5, 7, 11},Mod[#,13]]&] (* Vincenzo Librandi, Aug 05 2012 *)
  • PARI
    {forprime(p=2, 740, if(isprime(p%13), print1(p, ",")))} \\ Klaus Brockhaus, Oct 28 2009
    

Extensions

Edited by Klaus Brockhaus and R. J. Mathar, Oct 28 2009 and Oct 29 2009

A260181 Numbers whose last digit is prime.

Original entry on oeis.org

2, 3, 5, 7, 12, 13, 15, 17, 22, 23, 25, 27, 32, 33, 35, 37, 42, 43, 45, 47, 52, 53, 55, 57, 62, 63, 65, 67, 72, 73, 75, 77, 82, 83, 85, 87, 92, 93, 95, 97, 102, 103, 105, 107, 112, 113, 115, 117, 122, 123, 125, 127, 132, 133, 135, 137, 142, 143, 145, 147
Offset: 1

Views

Author

Wesley Ivan Hurt, Jul 17 2015

Keywords

Comments

Numbers ending in 2, 3, 5 or 7.
The subsequence of primes is A042993. - Michel Marcus, Jul 19 2015
From Wesley Ivan Hurt, Aug 15 2015, Sep 26 2015: (Start)
Ceiling(a(n)/2) = A047201(n).
Complement of (A197652 Union A262389). (End)

Crossrefs

Cf. A042993, A047201, A092620, subset of A118950.
Union of A017293, A017305, A017329 and A017353.
First differences are [1,2,2,5,...] = A002522(A140081(n-1)).

Programs

  • GAP
    a:=n->(5*n-4-(-1)^n+((3-(-1)^n)/2)*(-1)^((2*n+5-(-1)^n)/4))/2; List([1..60],n->a(n)); # Muniru A Asiru, Feb 16 2018
  • Magma
    [(5*n-4-(-1)^n+((3-(-1)^n) div 2)*(-1)^((2*n+5-(-1)^n) div 4))/2: n in [1..70]]; // Vincenzo Librandi, Jul 18 2015
    
  • Maple
    A260181:=n->(5*n-4-(-1)^n+((3-(-1)^n)/2)*(-1)^((2*n+5-(-1)^n)/4))/2: seq(A260181(n), n=1..100);
  • Mathematica
    CoefficientList[Series[(2 + x + 2 x^2 + 2 x^3 + 3 x^4)/((x - 1)^2*(1 + x + x^2 + x^3)), {x, 0, 100}], x]
    LinearRecurrence[{1, 0, 0, 1, -1}, {2, 3, 5, 7, 12}, 60] (* Vincenzo Librandi, Jul 18 2015 *)
    Table[(5n - 4 - (-1)^n + ((3 - (-1)^n)/2)*(-1)^((2*n + 5 - (-1)^n)/4))/2, {n, 100}] (* Wesley Ivan Hurt, Aug 11 2015 *)
  • PARI
    is(n)=my(m=digits(n));isprime(m[#m]) \\ Anders Hellström, Jul 19 2015
    
  • PARI
    A260181(n)=(n--)\4*10+prime(n%4+1) \\ is(n)=isprime(n%10) is much more efficient than the above. - M. F. Hasler, Sep 16 2016
    

Formula

G.f.: x*(2+x+2*x^2+2*x^3+3*x^4) / ((x-1)^2*(1+x+x^2+x^3)).
a(n) = a(n-1)+a(n-4)-a(n-5), n>5.
a(n) = (5*n-4-(-1)^n+((3-(-1)^n)/2)*(-1)^((2*n+5-(-1)^n)/4))/2.
Sum_{n>=1} (-1)^(n+1)/a(n) = (2*sqrt(5*sqrt(5+2*sqrt(5))) - 25*log(5) - 40*log(2) + 5*sqrt(5)*arccoth(843/2))/200. - Amiram Eldar, Jul 30 2024

A002382 Numbers of the form (p^2 - 49)/120 where p is prime.

Original entry on oeis.org

0, 1, 2, 4, 11, 15, 18, 23, 37, 44, 57, 78, 88, 95, 106, 134, 156, 205, 221, 232, 249, 310, 323, 414, 429, 452, 550, 576, 639, 667, 715, 785, 816, 837, 946, 1003, 1038, 1122, 1159, 1222, 1313, 1562, 1635, 1740, 1786, 1817, 1976, 2108, 2279, 2493, 2585, 2641
Offset: 1

Views

Author

Keywords

Comments

Primes p corresponding to a(n) are found in A003631(n+2) = A042993(n+3) = A097957(n+1). - Ray Chandler, Jul 29 2019

References

  • H. Gupta, On a conjecture of Chowla, Proc. Indian Acad. Sci., 5A (1937), 381-384.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Mathematica
    Select[(Prime[Range[150]]^2-49)/120,IntegerQ] (* Harvey P. Dale, Jan 19 2014 *)

Extensions

More terms from James Sellers, May 03 2000

A215374 Primes congruent to {0, 2, 3} mod 11.

Original entry on oeis.org

2, 3, 11, 13, 47, 79, 101, 113, 157, 167, 179, 211, 223, 233, 277, 311, 409, 421, 431, 443, 487, 509, 541, 563, 607, 619, 641, 673, 739, 751, 761, 773, 827, 839, 883, 937, 971, 1069, 1091, 1103, 1201, 1213, 1223, 1279, 1289, 1301, 1367, 1399, 1433, 1487
Offset: 1

Views

Author

Vincenzo Librandi, Aug 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(1500) | p mod 11 in [0, 2, 3]];
  • Mathematica
    Select[Prime[Range[400]],MemberQ[{0,2,3},Mod[#,11]]&]

A215375 Primes congruent to {0, 2, 3} mod 13.

Original entry on oeis.org

2, 3, 13, 29, 41, 67, 107, 197, 211, 223, 263, 353, 367, 379, 419, 431, 457, 509, 523, 587, 601, 613, 653, 691, 743, 757, 769, 809, 821, 887, 977, 991, 1069, 1237, 1277, 1289, 1303, 1367, 1381, 1433, 1459, 1471, 1511, 1523, 1549, 1601, 1627, 1667, 1693, 1783
Offset: 1

Views

Author

Vincenzo Librandi, Aug 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(2000) | p mod 13 in [0, 2, 3]];
  • Mathematica
    Select[Prime[Range[400]],MemberQ[{0,2,3},Mod[#,13]]&]

A215376 Primes congruent to {0, 2, 3} mod 17.

Original entry on oeis.org

2, 3, 17, 19, 37, 53, 71, 139, 173, 223, 241, 257, 359, 461, 479, 547, 563, 631, 683, 733, 751, 853, 887, 937, 971, 1039, 1091, 1193, 1277, 1447, 1481, 1499, 1549, 1567, 1583, 1601, 1669, 1753, 1787, 1873, 1889, 1907, 2111, 2161, 2179, 2213, 2281, 2297
Offset: 1

Views

Author

Vincenzo Librandi, Aug 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(2500) | p mod 17 in [0, 2, 3]];
  • Mathematica
    Select[Prime[Range[500]],MemberQ[{0,2,3},Mod[#,17]]&]

A215377 Primes congruent to {0, 2, 3} mod 19.

Original entry on oeis.org

2, 3, 19, 41, 59, 79, 97, 173, 193, 211, 269, 307, 383, 401, 421, 439, 743, 839, 857, 877, 953, 971, 991, 1009, 1123, 1181, 1237, 1409, 1427, 1447, 1523, 1579, 1637, 1693, 1789, 1979, 1997, 2017, 2111, 2131, 2207, 2339, 2377, 2473
Offset: 1

Views

Author

Vincenzo Librandi, Aug 09 2012

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(2500) | p mod 19 in [0, 2, 3]];
  • Mathematica
    Select[Prime[Range[500]],MemberQ[{0,2,3},Mod[#,19]]&]
Showing 1-10 of 10 results.