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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A132247 Twin primes congruent to {1, 11, 13, 17, 19, 29} mod 30.

Original entry on oeis.org

11, 13, 17, 19, 29, 31, 41, 43, 59, 61, 71, 73, 101, 103, 107, 109, 137, 139, 149, 151, 179, 181, 191, 193, 197, 199, 227, 229, 239, 241, 269, 271, 281, 283, 311, 313, 347, 349, 419, 421, 431, 433, 461, 463, 521, 523, 569, 571, 599, 601, 617, 619, 641, 643
Offset: 1

Views

Author

Omar E. Pol, Aug 18 2007

Keywords

Comments

Twin primes that are greater than 7. - Omar E. Pol, Oct 31 2013

Crossrefs

Formula

a(n) = A001097(n+3). - Michel Marcus, Nov 03 2013

A282323 Lesser of twin primes congruent to 17 (mod 30).

Original entry on oeis.org

17, 107, 137, 197, 227, 347, 617, 827, 857, 1277, 1427, 1487, 1607, 1667, 1697, 1787, 1877, 1997, 2027, 2087, 2237, 2267, 2657, 2687, 3167, 3257, 3467, 3527, 3557, 3767, 3917, 4127, 4157, 4217, 4337, 4517, 4547, 4637, 4787, 4967, 5417, 5477, 5657, 5867, 6197
Offset: 1

Views

Author

Martin Renner, Feb 11 2017

Keywords

Comments

The union of [this sequence and A282324] is A132242.
The union of [{3, 5}, A282321, this sequence and A060229] is the lesser of twin primes sequence A001359.
The union of [{3, 5, 7}, A282321 to A282326] is the twin primes sequence A001097.
A181605 without the 7. The proof works along the same lines as the proof in A282322. - R. J. Mathar, Feb 14 2017
Number of terms < 10^k: 0, 0, 1, 9, 64, 414, 2734, 19674, 146953, ... - Muniru A Asiru, Jan 09 2018

Examples

			From _Muniru A Asiru_, Jan 25 2018: (Start)
17 is a member because the pair (17, 19) is a twin prime, 17 < 19 and 17 mod 30 = 17.
137 is a member because the pair (137, 139) is a twin prime, 137 < 139 and 137 mod 30 = 17.
197 is a member because the pair (197, 199) is a twin prime, 197 < 199 and 197 mod 30 = 17.
(End)
		

Crossrefs

Programs

  • GAP
    P:=Filtered([1..400000], IsPrime);;
    P1:=List(Filtered(Filtered(List([1..Length(P)-1],n->[P[n],P[n+1]]),i->i[2]-i[1]=2),j->j[1] mod 30=17),k->k[1]);; # Muniru A Asiru, Jul 08 2017
  • Magma
    [p: p in PrimesUpTo(7000) | IsPrime(p+2) and p mod 30 eq 17 ]; // Vincenzo Librandi, Feb 13 2017
    
  • Maple
    a:={}:
    for i from 1 to 1229 do
      if isprime(ithprime(i)+2) and ithprime(i) mod 30 = 17 then
        a:={op(a),ithprime(i)}:
      fi:
    od:
    a;
  • Mathematica
    Select[17 + 30 Range[0, 220], PrimeQ[#] && PrimeQ[# + 2] &] (* Robert G. Wilson v, Jan 09 2018 *)
    Select[Partition[Prime[Range[1000]],2,1],#[[2]]-#[[1]]==2&&Mod[#[[1]],30]==17&][[;;,1]] (* or *) Select[Range[17,7000,30],AllTrue[#+{0,2},PrimeQ]&] (* Harvey P. Dale, Mar 02 2024 *)
  • PARI
    list(lim)=my(v=List(), p=2); forprime(q=3, lim+2, if(q-p==2 && q%30==19, listput(v, p)); p=q); Vec(v) \\ Charles R Greathouse IV, Feb 14 2017
    

A132242 Twin primes congruent to {17, 19} mod 30.

Original entry on oeis.org

17, 19, 107, 109, 137, 139, 197, 199, 227, 229, 347, 349, 617, 619, 827, 829, 857, 859, 1277, 1279, 1427, 1429, 1487, 1489, 1607, 1609, 1667, 1669, 1697, 1699, 1787, 1789, 1877, 1879, 1997, 1999, 2027, 2029, 2087, 2089, 2237, 2239, 2267, 2269, 2657, 2659
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Crossrefs

Programs

  • Mathematica
    a[0] = 7; a[n_] := a[n] = a[n - 1] + 10; Flatten[Table[If[PrimeQ[a[n]] && PrimeQ[a[n] + 2], {a[n],a[n] + 2}, {}], {n, 0, 1000}]] (* Roger L. Bagula, May 04 2008 *)

Extensions

More terms from Roger L. Bagula, May 04 2008

A132243 Twin primes congruent to {1, 29} mod 30.

Original entry on oeis.org

29, 31, 59, 61, 149, 151, 179, 181, 239, 241, 269, 271, 419, 421, 569, 571, 599, 601, 659, 661, 809, 811, 1019, 1021, 1049, 1051, 1229, 1231, 1289, 1291, 1319, 1321, 1619, 1621, 1949, 1951, 2129, 2131, 2309, 2311, 2339, 2341, 2549, 2551, 2729, 2731, 2789
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Comments

Twin primes of the form 5*n +- 1. - Bruno Berselli, Aug 26 2014

Crossrefs

Programs

  • Mathematica
    a[0] = 9; a[n_] := a[n] = a[n - 1] + 10; Flatten[Table[If[PrimeQ[a[n]] && PrimeQ[a[n] + 2], {a[n],a[n] + 2}, {}], {n, 0, 300}]] (* Roger L. Bagula, May 04 2008 *)
    Flatten[Select[#+{-1,1}&/@(5*Range[0,600,2]),AllTrue[#,PrimeQ]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Feb 21 2020 *)

Extensions

More terms from Roger L. Bagula, May 04 2008

A132241 Twin primes congruent to {11, 13} mod 30.

Original entry on oeis.org

11, 13, 41, 43, 71, 73, 101, 103, 191, 193, 281, 283, 311, 313, 431, 433, 461, 463, 521, 523, 641, 643, 821, 823, 881, 883, 1031, 1033, 1061, 1063, 1091, 1093, 1151, 1153, 1301, 1303, 1451, 1453, 1481, 1483, 1721, 1723, 1871, 1873
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Crossrefs

Programs

  • Mathematica
    a[0]=1;a[n_]:=a[n]=a[n-1]+10;Flatten[Table[If[PrimeQ[a[n]]&&PrimeQ[a[n]+2],{a[n],a[n]+2},{}],{n,0,200}]] (* Vincenzo Librandi, Aug 15 2012 *)

A141860 Primes congruent to 2 mod 15.

Original entry on oeis.org

2, 17, 47, 107, 137, 167, 197, 227, 257, 317, 347, 467, 557, 587, 617, 647, 677, 797, 827, 857, 887, 947, 977, 1097, 1187, 1217, 1277, 1307, 1367, 1427, 1487, 1607, 1637, 1667, 1697, 1787, 1847, 1877, 1907, 1997, 2027, 2087, 2207, 2237, 2267, 2297, 2357, 2417
Offset: 1

Views

Author

N. J. A. Sloane, Jul 11 2008

Keywords

Comments

2, and primes congruent to 17 mod 30. - Robert Israel, Jan 19 2016

Programs

  • Magma
    [ p: p in PrimesUpTo(5000) | p mod 15 eq 2 ]; // Vincenzo Librandi, Apr 19 2011
    
  • Maple
    select(isprime, [2, seq(i,i=17..1000, 30)]); # Robert Israel, Jan 19 2016
  • Mathematica
    Select[Prime[Range[400]],MemberQ[{2},Mod[#,15]]&] (* Vincenzo Librandi, Aug 15 2012 *)
    Select[Range[2,2500,15],PrimeQ] (* Harvey P. Dale, Dec 08 2012 *)
  • PARI
    lista(nn) = for(n=0, nn, if(ispseudoprime(p=15*n+2), print1(p, ", "))); \\ Altug Alkan, Jan 19 2016

Formula

{2} UNION A039949. - R. J. Mathar, Jul 20 2008

A132237 Primes congruent to {7, 23} mod 30.

Original entry on oeis.org

7, 23, 37, 53, 67, 83, 97, 113, 127, 157, 173, 233, 263, 277, 293, 307, 337, 353, 367, 383, 397, 443, 457, 487, 503, 547, 563, 577, 593, 607, 653, 683, 727, 743, 757, 773, 787, 863, 877, 907, 937, 953, 967, 983, 997, 1013, 1087, 1103
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Comments

Up to 4913, there are more primes of this form than composites. See also A132231 and A227869 (congruent to 7 only). - M. F. Hasler, Nov 02 2013

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(1300) | p mod 30 in [7, 23] ]; // Vincenzo Librandi, Aug 14 2012
    
  • Mathematica
    Select[Prime[Range[1000]],MemberQ[{7,23},Mod[#,30]]&] (* Vincenzo Librandi, Aug 14 2012 *)
  • PARI
    is_A132237(n)=setsearch([7,23],n%30)&&isprime(n) \\ - M. F. Hasler, Nov 02 2013

A132238 Primes congruent to {11, 13} mod 30.

Original entry on oeis.org

11, 13, 41, 43, 71, 73, 101, 103, 131, 163, 191, 193, 223, 251, 281, 283, 311, 313, 373, 401, 431, 433, 461, 463, 491, 521, 523, 613, 641, 643, 673, 701, 733, 761, 821, 823, 853, 881, 883, 911, 941, 971, 1031, 1033, 1061, 1063
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(1300) | p mod 30 in {11, 13} ]; // Vincenzo Librandi, Aug 14 2012
  • Mathematica
    Select[Prime[Range[200]],MemberQ[{11,13}, Mod[#,30]]&]  (* Harvey P. Dale, Mar 12 2011 *)

A253624 Initial members of prime sextuples (p, p+2, p+12, p+14, p+24, p+26).

Original entry on oeis.org

5, 17, 1277, 4217, 21587, 91127, 103967, 113147, 122027, 236867, 342047, 422087, 524957, 560477, 626597, 754967, 797567, 909317, 997097, 1322147, 1493717, 1698857, 1748027, 1762907, 2144477, 2158577, 2228507, 2398157, 2580647, 2615957
Offset: 1

Views

Author

Karl V. Keller, Jr., Jan 06 2015

Keywords

Comments

This sequence is primes p for which there exist three twin prime pairs (p, p+2), (p+12, p+14) and (p+24, p+26).
Excluding 5, this is a subsequence of each of the following: A128468 (a(n)=30n+17). A039949 (Primes of the form 30n-13), A181605 (twin primes ending in 7).
Note that not in all cases (p, p+2, p+12, p+14, p+24, p+26) are consecutive primes; the first p's for which (p, p+2, p+12, p+14, p+24, p+26) are consecutive primes are 4217, 21587, 91127, 103967, 236867, 342047, 422087, 560477, 797567, 909317, 1322147, 1493717, 1748027, 1762907, 2144477, 2158577, 2228507, 2615957 (not in OEIS). - Zak Seidov, May 16 2017

Examples

			For p = 17, the numbers 17, 19, 29, 31, 41, 43 are primes.
		

Crossrefs

Cf. A077800 (twin primes), A128468, A039949, A181605.

Programs

  • Maple
    select(t -> andmap(isprime, [t,t+2,t+12,t+14,t+24,t+26]),
    [5, seq(30*k+17,k=0..10^5)]); # Robert Israel, Jan 07 2015
  • Mathematica
    Select[Prime@ Range[2*10^5], Times @@ Boole@ PrimeQ[# + {2, 12, 14, 24, 26}] == 1 &] (* Michael De Vlieger, May 16 2017 *)
    Select[Prime[Range[200000]],AllTrue[#+{2,12,14,24,26},PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 15 2021 *)
  • Python
    from sympy import isprime
    for n in range(1,10000001,2):
      if isprime(n) and isprime(n+2) and isprime(n+12) and isprime(n+14) and isprime(n+24) and isprime(n+26): print(n,end=', ')
    
  • Python
    from sympy import isprime, primerange
    def aupto(limit):
      alst = []
      for p in primerange(2, limit+1):
        if all(map(isprime, [p+2, p+12, p+14, p+24, p+26])): alst.append(p)
      return alst
    print(aupto(3*10**6)) # Michael S. Branicky, May 17 2021

A132240 Primes congruent to {1, 29} mod 30.

Original entry on oeis.org

29, 31, 59, 61, 89, 149, 151, 179, 181, 211, 239, 241, 269, 271, 331, 359, 389, 419, 421, 449, 479, 509, 541, 569, 571, 599, 601, 631, 659, 661, 691, 719, 751, 809, 811, 839, 929, 991, 1019, 1021, 1049, 1051, 1109, 1171, 1201, 1229, 1231
Offset: 1

Views

Author

Omar E. Pol, Aug 15 2007

Keywords

Comments

For every prime p here, the cyclotomic polynomial Phi(15p,x) is flat.
Primes in A175887. [Reinhard Zumkeller, Jan 07 2012]

Crossrefs

Programs

  • Haskell
    a132240 n = a132240_list !! (n-1)
    a132240_list = [x | x <- a175887_list, a010051 x == 1]
    -- Reinhard Zumkeller, Jan 07 2012
    
  • Magma
    [ p: p in PrimesUpTo(1300) | p mod 30 in {1, 29} ]; // Vincenzo Librandi, Aug 14 2012
  • Mathematica
    Select[Prime[Range[1000]],MemberQ[{1,29},Mod[#,30]]&] (* Vincenzo Librandi, Aug 14 2012 *)
    Select[Flatten[#+{1,29}&/@(30Range[0,50])],PrimeQ] (* Harvey P. Dale, Sep 08 2021 *)
Previous Showing 11-20 of 32 results. Next