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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A281171 Numbers k such that (5*10^k + 37)/3 is prime.

Original entry on oeis.org

1, 2, 5, 9, 13, 20, 21, 32, 33, 56, 73, 81, 149, 313, 455, 753, 1013, 1166, 1304, 1679, 15758, 15896, 21801, 41353, 45421, 131090, 151007
Offset: 1

Views

Author

Robert Price, Jan 16 2017

Keywords

Comments

For k > 1, numbers k such that the digit 1 followed by k-2 occurrences of the digit 6 followed by the digits 79 is prime (see Example section).
a(28) > 2*10^5.

Examples

			2 is in this sequence because (5*10^2 + 37) / 3 = 179 is prime.
Initial terms and associated primes:
a(1) = 1, 29;
a(2) = 2, 179;
a(3) = 5, 166679;
a(4) = 9, 1666666679;
a(5) = 13, 16666666666679; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(5*10^# + 37) / 3] &]

Extensions

a(26)-a(27) from Robert Price, Mar 02 2018

A281732 Numbers k such that (8*10^k + 67)/3 is prime.

Original entry on oeis.org

3, 5, 9, 20, 26, 77, 101, 120, 308, 543, 869, 876, 1193, 1199, 1355, 1923, 3689, 3788, 4182, 6539, 19068, 26922, 38957, 58872, 61230, 72759
Offset: 1

Views

Author

Robert Price, Jan 28 2017

Keywords

Comments

For k > 1, numbers k such that the digit 2 followed by k-2 occurrences of the digit 6 followed by the digits 89 is prime (see Example section).
a(27) > 2*10^5.

Examples

			5 is in this sequence because (8*10^5 + 67)/3 = 2266689 7751 is prime.
Initial terms and associated primes:
a(1) = 3, 2689;
a(2) = 5, 266689;
a(3) = 9, 2666666689;
a(4) = 20, 266666666666666666689; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(8*10^# + 67)/3] &]

A281734 Numbers k such that (2*10^k + 529)/9 is prime.

Original entry on oeis.org

0, 1, 3, 4, 7, 9, 16, 18, 21, 33, 34, 45, 49, 57, 567, 595, 685, 867, 1867, 4204, 5311, 11493, 13923, 19116, 30471, 32038, 34551, 99408, 113631, 134364, 195399
Offset: 1

Views

Author

Robert Price, Jan 28 2017

Keywords

Comments

For k > 1, numbers k such that k-2 occurrences of the digit 2 followed by the digits 81 is prime (see Example section).
a(32) > 2*10^5.

Examples

			3 is in this sequence because (2*10^3 + 529)/9 = 281 is prime.
Initial terms and associated primes:
a(1) = 0, 59;
a(2) = 1, 61;
a(3) = 3, 281;
a(4) = 4, 2281;
a(5) = 7, 2222281; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(2*10^# + 529)/9] &]

Extensions

a(29)-a(31) from Robert Price, Jan 02 2018

A282456 Numbers k such that 18*10^k + 1 is prime.

Original entry on oeis.org

0, 1, 2, 4, 9, 12, 21, 55, 307, 332, 388, 820, 1593, 2432, 2438, 3372, 6270, 7437, 8268, 12135, 16588, 41397, 46126, 47910, 81091
Offset: 1

Views

Author

Robert Price, Feb 15 2017

Keywords

Comments

For k > 0, numbers k such that the digits 18 followed by k-1 occurrences of the digit 0 followed by the digit 1 is prime (see Example section).
a(26) > 10^5.

Examples

			2 is in this sequence because 18*10^2 + 1 = 1801 is prime.
Initial terms and associated primes:
a(1) = 0, 19;
a(2) = 1, 181;
a(3) = 2, 1801;
a(4) = 4, 180001;
a(5) = 9, 18000000001; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[18*10^# + 1] &]

A285377 Numbers k such that (41*10^k + 373)/9 is prime.

Original entry on oeis.org

3, 5, 6, 9, 11, 53, 105, 125, 137, 228, 789, 1259, 1661, 1697, 1785, 3737, 6054, 7614, 11819, 27366, 28320, 48678, 69321, 76067, 97085
Offset: 1

Views

Author

Robert Price, Apr 17 2017

Keywords

Comments

For k > 1, numbers k such that the digit 4 followed by k-2 occurrences of the digit 5 followed by the digits 97 is prime (see Example section).
a(26) > 2*10^5.

Examples

			5 is in this sequence because (41*10^5 + 373)/9 = 455597 is prime.
Initial terms and associated primes:
a(1) = 3, 4597;
a(2) = 5, 455597;
a(3) = 6, 4555597;
a(4) = 9, 4555555597;
a(5) = 11, 455555555597; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(41*10^# + 373)/9] &]

A286395 Numbers k such that (17*10^k + 67)/3 is prime.

Original entry on oeis.org

1, 3, 7, 8, 9, 11, 15, 19, 29, 55, 76, 159, 266, 311, 394, 908, 1732, 1875, 4335, 6334, 7641, 16421, 33721, 139239, 157705, 160143
Offset: 1

Views

Author

Robert Price, May 09 2017

Keywords

Comments

For k > 1, numbers k such that the digit 5 followed by k-2 occurrences of the digit 6 followed by the digits 89 is prime (see Example section).
a(27) > 2*10^5.

Examples

			3 is in this sequence because (17*10^3 + 67)/3 = 5689 is prime.
Initial terms and associated primes:
a(1) = 1, 79;
a(2) = 3, 5689;
a(3) = 7, 56666689;
a(4) = 8, 566666689;
a(5) = 9, 5666666689; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(17*10^# + 67)/3] &]

Extensions

a(24)-a(26) from Robert Price, Jan 24 2019

A289051 Numbers k such that 13*10^k + 1 is prime.

Original entry on oeis.org

1, 2, 3, 7, 16, 53, 95, 105, 125, 163, 358, 423, 562, 1774, 3459, 13957, 17962, 51179, 65963, 72808
Offset: 1

Views

Author

Robert Price, Jun 22 2017

Keywords

Comments

For k > 0, numbers k such that the digits 13 followed by k-1 occurrences of the digit 0 followed by the digit 1 is prime (see Example section).
a(21) > 10^5.

Examples

			2 is in this sequence because 13*10^3 + 1 = 1301 is prime.
Initial terms and associated primes:
a(1) = 1, 131;
a(2) = 2, 1301;
a(3) = 3, 13001;
a(4) = 7, 130000001;
a(5) = 16, 130000000000000001; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[13*10^# + 1] &]

A290962 Numbers k such that (13*10^k - 43)/3 is prime.

Original entry on oeis.org

1, 2, 4, 5, 8, 12, 55, 125, 136, 221, 224, 668, 1254, 2639, 4745, 5888, 8526, 9139, 13771, 17936, 27713, 38668, 44680, 73891, 135184, 200610, 215592, 247793, 258710, 291721
Offset: 1

Views

Author

Robert Price, Aug 15 2017

Keywords

Comments

For k > 1, numbers k such that the digit 4 followed by k-2 occurrences of the digit 3 followed by the digits 19 is prime (see Example section).
a(31) > 3*10^5.

Examples

			2 is in this sequence because (13*10^2 - 43)/3 = 419 is prime.
Initial terms and associated primes:
a(1) = 1, 29;
a(2) = 2, 419;
a(3) = 4, 43319;
a(4) = 5; 433319;
a(5) = 8, 433333319; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[1, 100000], PrimeQ[(13*10^# - 43)/3] &]
  • PARI
    isok(n) = ispseudoprime((13*10^n - 43)/3) \\ Altug Alkan, Aug 15 2017

Extensions

a(25) from Robert Price, Nov 28 2018
a(26)-a(30) from Robert Price, Oct 26 2023

A290964 Numbers k such that (35*10^k - 593)/9 is prime.

Original entry on oeis.org

3, 5, 6, 14, 24, 84, 87, 207, 734, 797, 1743, 2211, 3539, 5871, 5949, 6954, 8309, 10896, 12771, 22382, 35112, 38267, 69866, 121229, 125754, 133979
Offset: 1

Views

Author

Robert Price, Aug 15 2017

Keywords

Comments

For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 8 followed by the digits 23 is prime (see Example section).
a(27) > 2*10^5.

Examples

			5 is in this sequence because (35*10^5 - 593)/9 = 388823 is prime.
Initial terms and associated primes:
a(1) = 3, 3823;
a(2) = 5, 388823;
a(3) = 6, 3888823;
a(4) = 14; 388888888888823;
a(5) = 24, 3888888888888888888888823; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[2, 100000], PrimeQ[(35*10^# - 593)/9] &]
  • PARI
    isok(n) = ispseudoprime((35*10^n - 593)/9) \\ Altug Alkan, Aug 15 2017

Extensions

a(24)-a(26) from Robert Price, Jul 18 2018

A291609 Numbers k such that (49*10^k - 67)/9 is prime.

Original entry on oeis.org

1, 3, 4, 7, 10, 24, 37, 46, 63, 64, 91, 114, 367, 453, 1156, 1347, 1524, 7153, 10893, 13548, 15153, 43093, 61167, 184993
Offset: 1

Views

Author

Robert Price, Aug 27 2017

Keywords

Comments

For k > 1, numbers k such that the digit 5 followed by k-2 occurrences of the digit 4 followed by the digits 37 is prime (see Example section).
a(25) > 2*10^5.

Examples

			4 is in this sequence because (49*10^4 - 67)/9 = 54437 is prime.
Initial terms and associated primes:
a(1) = 1, 47;
a(2) = 3, 5437;
a(3) = 4, 54437;
a(4) = 7, 54444437;
a(5) = 10, 54444444437; etc.

Links

Crossrefs

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Programs

  • Mathematica
    Select[Range[1, 100000], PrimeQ[(49*10^# - 67)/9] &]

Extensions

a(24) from Robert Price, Mar 15 2019
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