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.

A200920 Least k such that (3^n+ k)*3^n + 1 is a prime number.

Original entry on oeis.org

1, 3, 1, 5, 3, 25, 11, 5, 13, 13, 9, 7, 3, 9, 17, 7, 29, 25, 71, 49, 7, 9, 7, 9, 11, 39, 7, 25, 107, 3, 67, 59, 49, 89, 67, 29, 113, 5, 33, 7, 19, 53, 3, 5, 47, 121, 39, 7, 407, 25, 7, 215, 29, 23, 89, 5, 33, 25, 113, 45, 49, 109, 53, 17, 109, 311, 91, 145, 43
Offset: 1

Views

Author

Michel Lagneau, Nov 24 2011

Keywords

Crossrefs

Cf. A191617, A191618, A191619, A191620, A200921, A200922, A200923.

Programs

  • Mathematica
    Table[k = 0; While[!PrimeQ[(3^n + k)*3^n + 1], k++]; k, {n, 72}]

A200922 Least k such that (3^n - k)*3^n - 1 is a prime number.

Original entry on oeis.org

1, 1, 1, 3, 7, 1, 1, 13, 17, 17, 7, 43, 25, 3, 41, 29, 57, 11, 21, 1, 25, 29, 17, 27, 15, 7, 11, 63, 15, 237, 73, 21, 43, 229, 1, 1, 73, 3, 253, 63, 7, 179, 3, 289, 97, 157, 7, 59, 95, 237, 33, 47, 3, 31, 43, 141, 157, 63, 137, 101, 387, 109, 157, 27, 29, 37
Offset: 1

Views

Author

Michel Lagneau, Nov 24 2011

Keywords

Crossrefs

Cf. A191617, A191618, A191619, A191620,A200920, A200921, A200923.

Programs

  • Mathematica
    Table[k = 0; While[!PrimeQ[(3^n - k)*3^n - 1], k++]; k, {n, 72}]

A200923 Least k such that (3^n - k)*3^n + 1 is a prime number.

Original entry on oeis.org

1, 1, 7, 1, 3, 1, 7, 5, 9, 29, 19, 1, 7, 49, 49, 9, 23, 1, 3, 29, 53, 39, 41, 35, 7, 5, 51, 33, 3, 81, 83, 15, 21, 31, 61, 69, 67, 87, 27, 5, 19, 55, 153, 35, 99, 31, 23, 49, 47, 95, 3, 115, 89, 55, 23, 61, 139, 49, 87, 5, 153, 87, 269, 113, 67, 207, 41, 33
Offset: 1

Views

Author

Michel Lagneau, Nov 24 2011

Keywords

Crossrefs

Cf. A191617, A191618, A191619, A191620, A200920, A200921, A200922.

Programs

  • Mathematica
    Table[k = 0; While[!PrimeQ[(3^n - k)*3^n + 1], k++]; k, {n, 72}]
lk[n_]:=Module[{c=3^n,k=1},While[!PrimeQ[(c-k)*c+1],k++];k]; Array[lk,70] (* Harvey P. Dale, Jul 15 2017 *)

A201134 Least k such that (5^n + k)*5^n - 1 is a prime number.

Original entry on oeis.org

1, 17, 1, 1, 5, 5, 55, 25, 37, 1, 53, 5, 53, 35, 47, 31, 127, 11, 1, 17, 11, 59, 71, 5, 155, 23, 11, 1, 13, 47, 43, 71, 17, 77, 53, 41, 13, 277, 47, 5, 143, 185, 157, 371, 43, 127, 119, 61, 221, 79, 131, 19, 49, 241, 7, 121, 11, 551, 157, 335, 13, 17, 13
Offset: 1

Views

Author

Michel Lagneau, Nov 27 2011

Keywords

Crossrefs

Cf. A191618, A200921.

Programs

  • Mathematica
    Table[k = 0; While[!PrimeQ[(5^n + k)*5^n - 1], k++]; k, {n, 85}]

A201457 Least k such that (7^n + k)*7^n - 1 is a prime number.

Original entry on oeis.org

5, 11, 1, 11, 23, 29, 17, 31, 13, 37, 61, 11, 35, 149, 17, 151, 17, 17, 17, 13, 59, 17, 73, 47, 43, 13, 113, 77, 119, 97, 125, 83, 13, 421, 103, 103, 77, 23, 23, 79, 5, 107, 7, 37, 59, 113, 11, 1, 169, 887, 137, 41, 113, 71, 277, 413, 97, 91, 227, 337, 97, 353, 233, 953, 5, 139, 77, 473, 73, 167, 275, 67, 49, 97, 365, 73, 223, 241, 115
Offset: 1

Views

Author

Michel Lagneau, Dec 01 2011

Keywords

Crossrefs

Cf. A191618, A200921, A201134.

Programs

  • Mathematica
     Table[k = 0; While[!PrimeQ[(7^n + k)*7^n - 1], k++]; k, {n, 85}]
Showing 1-5 of 5 results.

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