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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A139448 Numbers n such that primorial(n)/2 - 64 is prime.

Original entry on oeis.org

4, 5, 6, 7, 10, 13, 17, 18, 28, 32, 35, 38, 89, 115, 117, 224, 241, 353, 440, 1153, 2585, 3075, 3456, 4895, 7483, 7649, 8197, 8625, 13285, 19849, 24179, 24442
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(33) > 25000. - Robert Price, Apr 10 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 64]&&k>64, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a
Flatten[Position[Rest[FoldList[Times,1,Prime[Range[600]]]],?(PrimeQ[ #/2-64]&&#/2>64&)]] (* _Harvey P. Dale, Mar 05 2013 *)
Select[Range[4, 100], PrimeQ[Product[Prime[k], {k, 1, #}]/2 - 64] &] (* Robert Price, Apr 10 2017 *)

Extensions

a(18)-a(19) from Harvey P. Dale, Mar 05 2013
Drop 2 and correct programs, a(20)-a(21) from Ray Chandler, Jun 16 2013
a(22)-a(32) from Robert Price, Apr 10 2017

A139449 Numbers n such that primorial(n)/2 + 128 is prime.

Original entry on oeis.org

2, 4, 5, 7, 8, 10, 11, 23, 25, 67, 87, 125, 141, 242, 255, 258, 279, 316, 449, 578, 871, 1072, 1886, 2071, 3315, 18225
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(27) > 25000. - Robert Price, Apr 10 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 128], Print[n]; AppendTo[a, n]], {n, 325}]; a
Select[Range[0, 25000], PrimeQ[Product[Prime[k], {k, 1, #}]/2 + 128] &] (* Robert Price, Apr 10 2017 *)

Extensions

a(18)-a(24) from Ray Chandler, Jun 16 2013
a(25)-a(26) from Robert Price, Apr 10 2017

A139450 Numbers n such that primorial(n)/2 - 128 is prime.

Original entry on oeis.org

6, 7, 17, 26, 32, 40, 43, 391, 435, 1509, 1629, 2906, 3525, 5670, 8586, 12103, 12528, 16682
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(19) > 25,000. - Robert Price, May 02 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 128]&&k>128, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a

Extensions

Drop 3,4 and correct program, a(9)-a(12) from Ray Chandler, Jun 16 2013
a(13)-a(18) from Robert Price, May 02 2017

A139451 Numbers n such that primorial(n)/2 + 256 is prime.

Original entry on oeis.org

1, 3, 6, 7, 8, 13, 22, 33, 53, 58, 62, 142, 189, 220, 479, 496, 503, 760, 1464, 6503, 9477, 13861, 23881
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(24) > 25000. - Robert Price, May 21 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 256], Print[n]; AppendTo[a, n]], {n, 325}]; a

Extensions

a(1)=1 inserted and program corrected, a(15)-a(19) from Ray Chandler, Jun 16 2013
a(20)-a(23) from Robert Price, May 21 2017

A139452 Numbers n such that primorial(n)/2 - 256 is prime.

Original entry on oeis.org

6, 8, 16, 27, 66, 74, 168, 253, 458, 1310, 2665, 2681, 2718, 2836, 4921, 7356, 11466
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(18) > 25000. - Robert Price, May 22 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 256]&&k>256, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a

Extensions

Drop 3,4 and correct program, a(9)-a(14) from Ray Chandler, Jun 16 2013
a(15)-a(17) from Robert Price, May 22 2017

A139453 Numbers n such that primorial(n)/2 + 512 is prime.

Original entry on oeis.org

4, 5, 6, 7, 9, 12, 73, 129, 142, 144, 253, 455, 531, 734, 1009, 1193, 1553, 2449, 3309, 13534, 17513, 17832, 22852
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(24) > 25000. - Robert Price, May 22 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 512], Print[n]; AppendTo[a, n]], {n, 325}]; a

Extensions

a(12)-a(18) from Ray Chandler, Jun 16 2013
a(19)-a(23) from Robert Price, May 22 2017

A139454 Numbers n such that primorial(n)/2 - 512 is prime.

Original entry on oeis.org

5, 6, 9, 10, 11, 12, 17, 18, 23, 36, 48, 62, 87, 112, 131, 400, 1606, 6136, 6519, 11700
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(21) > 25000. - Robert Price, Jul 02 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 512]&&k>512, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a (* corrected by Ray Chandler, Jun 16 2013 *)

Extensions

Dropped 2 and a(16)-a(17) from Ray Chandler, Jun 16 2013
a(18)-a(20) from Robert Price, Jul 02 2017

A139455 Numbers n such that primorial(n)/2 + 1024 is prime.

Original entry on oeis.org

3, 4, 5, 7, 11, 14, 15, 22, 30, 32, 37, 53, 83, 123, 156, 212, 215, 314, 331, 417, 555, 930, 3809, 3945, 15738
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(26) > 25000. - Robert Price, Jul 02 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

  • Mathematica
    k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 1024], Print[n]; AppendTo[a, n]], {n, 325}]; a
  • PARI
    isok(n) = isprime(1024+prod(k=2, n, prime(k))); \\ Michel Marcus, Jul 02 2017

Extensions

a(18)-a(22) from Ray Chandler, Jun 16 2013
a(23)-a(25) from Robert Price, Jul 02 2017

A139456 Numbers n such that primorial(n)/2 - 1024 is prime.

Original entry on oeis.org

5, 9, 10, 11, 16, 17, 20, 59, 96, 98, 318, 387, 938, 978, 1764, 8298, 10632, 11796, 19982
Offset: 1

Views

Author

Artur Jasinski, Apr 21 2008

Keywords

Comments

a(20) > 25000. - Robert Price, Sep 28 2017

Crossrefs

Cf. A067026, A067027, A139439-A139457, A103514.

Programs

Extensions

Drop 2,3,4 and correct program, a(12)-a(15) from Ray Chandler, Jun 16 2013
a(16)-a(19) from Robert Price, Sep 28 2017

A139460 a(n) = m such that 2*prime(n+m+1) + (product of n successive odd primes) is prime.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 3, 1, 1, 2, 1, 1, 9, 2, 7, 21, 7, 25, 4, 3, 18, 7, 4, 7, 11, 5, 1, 1, 61, 5, 20, 6, 22, 16, 11, 17, 1, 70, 6, 5, 5, 22, 9, 52, 108, 16, 1, 32, 42, 15, 5, 66, 6, 8, 3, 38, 17, 4, 23, 93, 8, 16, 6, 1, 39, 7, 9, 10, 21, 57, 40, 2, 15, 39, 16, 7, 5, 13, 138, 95, 58, 8, 47, 11, 39
Offset: 1

Views

Author

Artur Jasinski, Apr 22 2008; definition corrected May 09 2008

Keywords

Comments

Or, a(n) = m such that primorial(n+1)/2+2*prime(n+m+1) is prime.
For positions of 1's in this sequence see A139461

Crossrefs

Cf. A067026, A067027, A139439, A139440, A139441, A139442, A139443, A139444, A139445, A139446, A139447, A139448, A139449, A139450, A139451, A139452, A139453, A139454, A139455, A139456, A139457, A103514, A139460, A139461, A139462, A139463.

Programs

  • Mathematica
    k = 1; a = {}; Do[k = k*Prime[n]; m = 1; While[ ! PrimeQ[k + 2*Prime[n + m]], m++ ]; Print[m]; AppendTo[a, m], {n, 2, 200}]; a (*Artur Jasinski*)
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