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.

A206037 Values of the difference d for 3 primes in arithmetic progression with the minimal start sequence {3 + j*d}, j = 0 to 2.

Original entry on oeis.org

2, 4, 8, 10, 14, 20, 28, 34, 38, 40, 50, 64, 68, 80, 94, 98, 104, 110, 124, 134, 154, 164, 178, 188, 190, 208, 220, 230, 238, 248, 260, 280, 308, 314, 328, 344, 370, 418, 428, 430, 440, 454, 458, 484, 518, 544, 560, 574, 584, 610, 614, 628, 638, 640, 644, 650
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.
Numbers k such that k+3 and 2k+3 are both primes.
Equivalently, integers d such that the largest possible arithmetic progression (AP) of primes with common difference d has exactly 3 elements (see example). These 3 elements are not necessarily consecutive primes. In fact, for each term d, there exists only one such AP of primes, and this one starts always with A342309(d) = 3, so this AP is (3, 3+d, 3+2d). - Bernard Schott, Jan 15 2023

Examples

			d = 8 then {3, 3 + 1*8, 3 + 2*8} = {3, 11, 19}, which is 3 primes in arithmetic progression.
		

Crossrefs

Largest AP of prime numbers with k elements: A007921 (k=1), A359408 (k=2), this sequence (k=3), A359409 (k=4), A206039 (k=5), A359410 (k=6), A206041 (k=7).

Programs

  • Magma
    [n: n in [1..700] | IsPrime(3+n) and IsPrime(3+2*n)]; // Vincenzo Librandi, Dec 28 2015
  • Maple
    filter := d -> isprime(3+d) and isprime(3+2*d) : select(filter, [$(1 .. 650)]); # Bernard Schott, Jan 16 2023
  • Mathematica
    t={}; Do[If[PrimeQ[{3, 3 + d, 3 + 2*d}] == {True, True, True}, AppendTo[t, d]], {d, 1000}]; t
    Select[Range[2,700,2],And@@PrimeQ[{3+#,3+2#}]&] (* Harvey P. Dale, Sep 25 2013 *)
  • PARI
    for(n=1, 1e3, if(isprime(n + 3) && isprime(2*n + 3), print1(n, ", "))); \\ Altug Alkan, Dec 27 2015
    

Formula

a(n) = 2 * A115334(n). - Wesley Ivan Hurt, Feb 06 2014
m is a term iff A123556(m) = 3. - Bernard Schott, Jan 15 2023

A206045 Numbers d such that 11 + j*d is prime for j = 0 to 10.

Original entry on oeis.org

1536160080, 4911773580, 25104552900, 77375139660, 83516678490, 100070721660, 150365447400, 300035001630, 318652145070, 369822103350, 377344636200, 511688932650, 580028072610, 638663371710, 701534299830, 745828915650, 776625236100, 883476548850, 925639075620, 956863233690
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

Original name: Values of the difference d for 11 primes in arithmetic progression with the minimal start sequence {11 + j*d}, j = 0 to 10.
The computations were done without any assumptions on the form of d. 21st term is greater than 10^12.
All terms are multiples of 210=2*3*5*7. - Zak Seidov, May 16 2015
Equivalently, integers d such that the longest possible arithmetic progression (AP) of primes with common difference d has exactly 11 elements (see example). These 11 elements are not necessarily consecutive primes. In fact, here, for each term d, there exists only one such AP of primes, and this one always starts with A342309(d) = 11, so this unique AP is (11, 11+d, 11+2d, 11+3d, 11+4d, 11+5d, 11+6d, 11+7d, 11+8d, 11+9d, 11+10d). - Bernard Schott, Mar 08 2023

Examples

			d = 4911773580 then {11, 4911773591, 9823547171, 14735320751, 19647094331, 24558867911, 29470641491, 34382415071, 39294188651, 44205962231, 49117735811} which is 11 primes in arithmetic progression.
		

References

  • Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 139.

Crossrefs

Common differences for longest possible APs of primes with exactly k elements: A007921 (k=1), A359408 (k=2), A206037 (k=3), A359409 (k=4), A206039 (k=5), A359410 (k=6), A206041 (k=7), A360146 (k=10), this sequence (k=11).

Programs

  • Mathematica
    a = 11; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d, a + 6*d, a + 7*d, a + 8*d, a + 9*d, a + 10*d}] == {True, True, True, True, True, True, True, True, True, True, True}, Print[d]], {d, 210,10^12, 210}] (* corrected by Zak Seidov, May 16 2015 *)
    Select[Range[210,10^12,210],AllTrue[Range[0,10]#+11,PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 28 2016 *)
  • PARI
    is(n)=for(j=1,10, if(!isprime(j*n+11), return(0))); 1 \\ Charles R Greathouse IV, May 18 2015

Formula

m is a term iff A123556(m) = 11. - Bernard Schott, Mar 08 2023

Extensions

New name from Charles R Greathouse IV, May 18 2015

A206039 Values of the difference d for 5 primes in arithmetic progression with the minimal start sequence {5 + j*d}, j = 0 to 4.

Original entry on oeis.org

6, 12, 42, 48, 96, 126, 252, 426, 474, 594, 636, 804, 1218, 1314, 1428, 1566, 1728, 1896, 2106, 2574, 2694, 2898, 3162, 3366, 4332, 4368, 4716, 4914, 4926, 4962, 5472, 5586, 5796, 5838, 6048, 7446, 7572, 7818, 8034, 8958, 9168, 9204, 9714
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.
All terms are multiples of 6. - Zak Seidov, Jan 07 2014
Equivalently, integers d such that the largest possible arithmetic progression (AP) of primes with common difference d has exactly 5 elements (see example). These 5 elements are not necessarily consecutive primes. In fact, for each term d, there exists only one such AP of primes, and this one always starts with A342309(d) = 5, so this unique AP is (5, 5+d, 5+2d, 5+3d, 5+4d). - Bernard Schott, Jan 25 2023

Examples

			d = 12 then {5, 5 + 1*12, 5 + 2*12, 5 + 3*12, 5 + 4*12} = {5, 17, 29, 41, 53}, which is 5 primes in arithmetic progression.
		

Crossrefs

Largest AP of prime numbers with exactly k elements: A007921 (k=1), A359408 (k=2), A206037 (k=3), A359409 (k=4), this sequence (k=5), A359410 (k=6), A206041 (k=7), A360146 (k=10), A206045 (k=11).

Programs

  • Maple
    filter := d -> isprime(5+d) and isprime(5+2*d) and isprime(5+3*d) and isprime(5+4*d) : select(filter, [$(1 .. 10000)]); # Bernard Schott, Jan 25 2023
  • Mathematica
    t={}; Do[If[PrimeQ[{5, 5 + d, 5 + 2*d, 5 + 3*d, 5 +4*d}] == {True, True, True, True, True}, AppendTo[t, d]], {d, 10000}]; t
    Select[Range[10000],AllTrue[5+#*Range[0,4],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 09 2015 *)

Formula

m is a term iff A123556(m) = 3. - Bernard Schott, Jan 25 2023

A206041 Values of the difference d for 7 primes in arithmetic progression with the minimal start sequence {7 + j*d}, j = 0 to 6.

Original entry on oeis.org

150, 2760, 3450, 9150, 14190, 20040, 21240, 63600, 76710, 117420, 122340, 134250, 184470, 184620, 189690, 237060, 274830, 312000, 337530, 379410, 477630, 498900, 514740, 678750, 707850, 1014540, 1168530, 1180080, 1234530, 1251690, 1263480, 1523520, 1690590
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.
All terms are multiples of 30. - Zak Seidov, Jan 07 2014.
Equivalently, integers d such that the longest possible arithmetic progression (AP) of primes with common difference d has exactly 7 elements (see example). These 7 elements are not necessarily consecutive primes. In fact, for each term d, there exists only one such AP of primes, and this one always starts with A342309(d) = 7, so this unique AP is (7, 7+d, 7+2d, 7+3d, 7+4d, 7+5d, 7+6d). - Bernard Schott, Feb 12 2023

Examples

			d = 150 then {7, 7 + 1*150, 7 + 2*150, 7 + 3*150, 7 + 4*150, 7 + 5*150, + 7 + 6*150} = {7, 157, 307, 457, 607, 757, 907} which is 7 primes in arithmetic progression.
		

Crossrefs

Longest AP of prime numbers with exactly k elements: A007921 (k=1), A359408 (k=2), A206037 (k=3), A359409 (k=4), A206039 (k=5), A359410 (k=6), this sequence (k=7), A360146 (k=10), A206045 (k=11).

Programs

  • Maple
    filter := d -> isprime(7+d) and isprime(7+2*d) and isprime(7+3*d) and isprime(7+4*d) and isprime(7+5*d) and isprime(7+6*d): select(filter, [$(1 .. 1700000)]); # Bernard Schott, Feb 13 2023
  • Mathematica
    a = 7; t = {}; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d, a + 6*d}] == {True, True, True, True, True, True, True}, AppendTo[t,d]], {d, 200000}]; t

Formula

m is a term iff A123556(m) = 7. - Bernard Schott, Feb 12 2023

A206042 Values of the difference d for 8 primes in arithmetic progression with the minimal start sequence {11 + j*d}, j = 0 to 7.

Original entry on oeis.org

1210230, 2523780, 4788210, 10527720, 12943770, 19815600, 22935780, 28348950, 28688100, 32671170, 43443330, 47330640, 51767520, 54130440, 59806740, 60625110, 63721770, 66761940, 77811300, 80892420, 87931620, 90601140, 102994500, 108310650, 115209570, 117639480
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.

Examples

			d = 2523780 then {11 + j*d}, j = 0 to 7, is {11, 2523791, 5047571, 7571351, 10095131, 12618911, 15142691, 17666471} which is 8 primes in arithmetic progression.
		

Crossrefs

Programs

  • Mathematica
    a = 11; t = {}; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d, a + 6*d, a + 7*d}] == {True, True, True, True, True, True, True, True},
       AppendTo[t,d]], {d, 0, 200000000}]; t
    Select[Range[117640000],AllTrue[11+#*Range[0,7],PrimeQ]&] (* Harvey P. Dale, Dec 31 2021 *)

A206044 Values of the difference d for 10 primes in arithmetic progression with the minimal start sequence {11 + j*d}, j = 0 to 9.

Original entry on oeis.org

224494620, 246632190, 301125300, 1536160080, 1760583300, 4012387260, 4911773580, 7158806130, 8155368060, 15049362300, 15908029410, 18191167890, 21238941150, 22519921410, 25104552900, 25837762860, 27109731180, 27380574480, 27925987530, 29165157630
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d. 181st term is greater than 10^12.

Examples

			d = 301125300 then {11, 301125311, 602250611, 903375911, 1204501211, 1505626511, 1806751811, 2107877111, 2409002411, 2710127711} which is 10 primes in arithmetic progression.
		

Crossrefs

Programs

  • Mathematica
    a = 11; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d, a + 6*d, a + 7*d, a + 8*d, a + 9*d}] == {True, True, True, True, True, True, True, True, True, True}, Print[d]], {d, 600000000, 2}]

Extensions

Typo in Name fixed by Zak Seidov, Jan 12 2014

A206043 Values of the difference d for 9 primes in arithmetic progression with the minimal start sequence {11 + j*d}, j = 0 to 8.

Original entry on oeis.org

32671170, 54130440, 59806740, 145727400, 224494620, 246632190, 280723800, 301125300, 356845020, 440379870, 486229380, 601904940, 676987920, 777534660, 785544480, 789052530, 799786890, 943698210, 1535452800, 1536160080, 1760583300, 1808008020
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.

Examples

			d = 54130440 then {11, 54130451, 108260891, 162391331, 216521771, 270652211, 324782651, 378913091, 433043531} which is 9 primes in arithmetic progression.
		

Crossrefs

Programs

  • Mathematica
    a = 11; t = {}; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d, a + 6*d, a + 7*d, a + 8*d}] == {True, True, True, True, True, True, True, True, True}, AppendTo[t,d]], {d, 10^9}]; t
  • PARI
    forstep(k=210,1e10,210,forstep(p=k+11,8*k+11,k,if(!isprime(p), next(2)));print1(k", ")) \\ Charles R Greathouse IV, Feb 09 2012

Extensions

a(20) corrected by Charles R Greathouse IV, Feb 09 2012

A206040 Values of the difference d for 6 primes in arithmetic progression with the minimal start sequence {7 + j*d}, j = 0 to 5.

Original entry on oeis.org

30, 150, 930, 2760, 3450, 4980, 9150, 14190, 19380, 20040, 21240, 28080, 33930, 57660, 59070, 63600, 69120, 76710, 80340, 81450, 97380, 100920, 105960, 114750, 117420, 122340, 134250, 138540, 143670, 150090, 164580, 184470, 184620, 189690, 231360, 237060
Offset: 1

Views

Author

Sameen Ahmed Khan, Feb 03 2012

Keywords

Comments

The computations were done without any assumptions on the form of d.

Examples

			d = 150 then {7, 7 + 1*150, 7 + 2*150, 7 + 3*150, 7 + 4*150, 7 + 5*150} = {7, 157, 307, 457, 607, 757} which is 6 primes in arithmetic progression.
		

Crossrefs

Programs

  • Mathematica
    a = 7; t = {}; Do[If[PrimeQ[{a, a + d, a + 2*d, a + 3*d, a + 4*d, a + 5*d}] == {True, True, True, True, True, True}, AppendTo[t,d]], {d, 300000}]; t
    Select[Range[250000],AllTrue[7+#*Range[0,5],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 26 2017 *)
Showing 1-8 of 8 results.