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 1-5 of 5 results.

A125241 Numbers k such that binomial(4k, k) + 1 is prime.

Original entry on oeis.org

0, 1, 2, 6, 10, 11, 19, 28, 80, 123, 141, 147, 154, 198, 200, 346, 851, 887, 1038, 1329, 2045, 3228, 3274, 3588, 6794, 8045, 11911, 12184, 12327, 12515, 20089, 38173, 41026, 48914, 71772, 72130, 100726
Offset: 1

Views

Author

Alexander Adamchuk, Nov 25 2006

Keywords

Crossrefs

Cf. A125240 = numbers n such that binomial(4n, n) - 1 is prime. Cf. A066699 = numbers n such that binomial(2n, n) + 1 is prime. Cf. A066726 = numbers n such that binomial(2n, n) - 1 is prime. Cf. A125220, A125221, A125242, A125243, A125244, A125245.

Programs

  • Mathematica
    Do[f=Binomial[4n, n]+1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]
Select[Range[8100],PrimeQ[Binomial[4#,#]+1]&] (* Harvey P. Dale, Aug 24 2014 *)

Extensions

More terms from Ryan Propper, Mar 28 2007
a(1)=0 added by Robert Price, May 01 2019
a(27)-a(34) from Robert Price, May 01 2019
a(35)-a(37) from Georg Grasegger, Jun 02 2025

A125242 Numbers k such that binomial(5k, k) - 1 is prime.

Original entry on oeis.org

5, 71, 111, 187, 239, 247, 473, 628, 847, 1478, 2687, 3530, 5175, 9113, 10968, 15039, 28929, 35649, 43481, 44455, 51269, 63975, 71723
Offset: 1

Views

Author

Alexander Adamchuk, Nov 25 2006

Keywords

Comments

a(24) > 10^5. Robert Price, Nov 16 2024

Crossrefs

Cf. A125243 = numbers n such that binomial(5n, n) + 1 is prime. Cf. A066699 = numbers n such that binomial(2n, n) + 1 is prime. Cf. A066726 = numbers n such that binomial(2n, n) - 1 is prime. Cf. A125220, A125221, A125240, A125241, A125244, A125245.

Programs

  • Mathematica
    Do[f=Binomial[5n, n]-1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]
Select[Range[45000],PrimeQ[Binomial[5#,#]-1]&] (* Harvey P. Dale, Jan 02 2022 *)

Extensions

More terms from Ryan Propper, Jan 06 2007
a(15)-a(20) from Robert Price, May 03 2019
a(21)-a(23) from Robert Price, Nov 16 2024

A125243 Numbers k such that binomial(5k, k) + 1 is prime.

Original entry on oeis.org

0, 22, 86, 154, 160, 488, 705, 958, 975, 1262, 1932, 2845, 12718, 14434, 20337, 38834, 40433, 44874, 68279, 68724, 89911, 104765
Offset: 1

Views

Author

Alexander Adamchuk, Nov 25 2006

Keywords

Comments

a(22) > 100000. - Robert Price, Mar 20 2025

Crossrefs

Cf. A125242, A066699, A066726.
Cf. A125220, A125221, A125240, A125241, A125244, A125245.

Programs

  • Mathematica
    Do[f=Binomial[5n, n]+1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]

Extensions

More terms from Ryan Propper, Jan 05 2007
a(1)=0 prepended and a(13)-a(18) added by Robert Price, May 11 2019
a(19)-a(21) from Robert Price, Mar 20 2025
a(22) from Georg Grasegger, May 06 2025

A125244 Numbers k such that binomial(6k, k) - 1 is prime.

Original entry on oeis.org

1, 7, 17, 22, 43, 343, 381, 461, 543, 923, 1045, 1182, 1486, 1839, 5643, 8260, 9009, 10947, 11793, 15915, 25151, 50923, 57095, 59977, 76513, 83383
Offset: 1

Views

Author

Alexander Adamchuk, Nov 25 2006

Keywords

Comments

a(27) > 100000. - Robert Price, May 09 2025

Crossrefs

Cf. A125245 = numbers n such that binomial(6n, n) + 1 is prime. Cf. A066699 = numbers n such that binomial(2n, n) + 1 is prime. Cf. A066726 = numbers n such that binomial(2n, n) - 1 is prime. Cf. A125220, A125221, A125240, A125241, A125242, A125243.

Programs

  • Mathematica
    Do[f=Binomial[6n, n]-1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]

Extensions

More terms from Ryan Propper, Mar 28 2007
a(18)-a(21) from Robert Price, May 13 2019
a(22)-a(23) from Georg Grasegger, May 08 2025
a(24)-a(26) from Robert Price, May 09 2025

A125245 Numbers k such that binomial(6k, k) + 1 is prime.

Original entry on oeis.org

0, 1, 2, 4, 10, 15, 98, 111, 118, 236, 280, 512, 1284, 1303, 1818, 2525, 2692, 4620, 8405, 11539, 13190, 21525, 30338, 48069, 50687, 56208, 56620, 81091, 101488
Offset: 1

Views

Author

Alexander Adamchuk, Nov 25 2006

Keywords

Comments

a(25) > 50000. - Robert Price, May 13 2019

Crossrefs

Cf. A125244 = numbers n such that binomial(6n, n) - 1 is prime. Cf. A066699 = numbers n such that binomial(2n, n) + 1 is prime. Cf. A066726 = numbers n such that binomial(2n, n) - 1 is prime. Cf. A125220, A125221, A125240, A125241, A125242, A125243.

Programs

  • Mathematica
    Do[f=Binomial[6n, n]+1; If[PrimeQ[f], Print[n]], {n, 1, 1000}]

Extensions

More terms from Ryan Propper, Mar 28 2007
a(1)=0 and a(20)-a(24) from Robert Price, May 13 2019
a(25)-a(29) from Georg Grasegger, Jun 23 2025
Showing 1-5 of 5 results.

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