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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A276114 Numbers k such that (101*10^k - 17)/3 is prime.

Original entry on oeis.org

1, 2, 15, 17, 26, 41, 56, 59, 121, 137, 224, 506, 611, 836, 937, 1079, 1829, 2315, 2666, 2879, 6661, 7167, 14021, 15459, 32924, 73346, 176815, 177302
Offset: 1

Views

Author

Robert Price, Aug 18 2016

Keywords

Comments

Numbers k such that the digits 33 followed by k-1 occurrences of the digit 6 followed by the digit 1 is prime (see Example section).
a(29) > 2*10^5.

Examples

			2 is in this sequence because (101*10^2 - 17)/3 = 3361 is prime.
Initial terms and associated primes:
a(1) = 1, 331;
a(2) = 2, 3361;
a(3) = 15, 33666666666666661;
a(4) = 17, 3366666666666666661;
a(5) = 26, 3366666666666666666666666661, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(101*10^# - 17)/3] &]
  • PARI
    is(n)=ispseudoprime((101*10^n  - 17)/3) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(27)-a(28) from Robert Price, Feb 05 2020

A276118 Numbers k such that 42 * 10^k + 1 is prime.

Original entry on oeis.org

0, 1, 2, 4, 13, 19, 39, 62, 76, 79, 109, 184, 222, 265, 370, 626, 670, 679, 763, 1950, 2174, 3379, 7369, 9087, 34990, 47535, 97970
Offset: 1

Views

Author

Robert Price, Aug 20 2016

Keywords

Comments

For k > 0, numbers k such that the digits 42 followed by k - 1 occurrences of the digit 0 followed by the digit 1 is prime (see the Example section).
a(28) > 10^5.

Examples

			4 is in this sequence because 42*10^4+1 = 420001 is prime.
Initial terms and associated primes:
a(1) = 0, 43;
a(2) = 1, 421;
a(3) = 2, 4201;
a(4) = 4, 420001;
a(5) = 13, 420000000000001, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[42 * 10^# + 1] &]
  • PARI
    is(n)=ispseudoprime(42*10^n+1) \\ Charles R Greathouse IV, Jun 13 2017

A276311 Numbers k such that (13*10^k + 197)/3 is prime.

Original entry on oeis.org

1, 2, 4, 5, 17, 21, 23, 28, 41, 43, 51, 59, 105, 115, 131, 273, 585, 1519, 2303, 4791, 4921, 6019, 7833, 25711, 27319, 32497, 37975, 49381, 87199
Offset: 1

Views

Author

Robert Price, Aug 29 2016

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 99 is prime (see the Example section).
a(30) > 10^5.

Examples

			4 is in this sequence because (13*10^4 + 197)/3 = 43399 is prime.
Initial terms and associated primes:
a(1) = 1, 109;
a(2) = 2, 499;
a(3) = 4, 43399;
a(4) = 5, 433399;
a(5) = 17, 433333333333333399, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(13*10^# + 197)/3] &]
  • PARI
    is(n)=ispseudoprime((13*10^n+197)/3) \\ Charles R Greathouse IV, Jun 13 2017

A276322 Numbers k such that (13*10^k + 83) / 3 is prime.

Original entry on oeis.org

1, 2, 5, 7, 17, 18, 25, 60, 64, 66, 118, 125, 1021, 1901, 2273, 2524, 6048, 7098, 8281, 11634, 13843, 16098, 18652, 18661, 20570, 32291, 34181, 59928, 65297, 86546
Offset: 1

Views

Author

Robert Price, Sep 01 2016

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 61 is prime (see Example section).
a(31) > 2*10^5.

Examples

			5 is in this sequence because (13*10^5 + 83) / 3 = 433361 is prime.
Initial terms and associated primes:
a(1) = 1, 71;
a(2) = 2, 461;
a(3) = 5, 433361;
a(4) = 7, 43333361;
a(5) = 17, 433333333333333361, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(13*10^# + 83) / 3] &]
  • PARI
    is(n)=ispseudoprime((13*10^n + 83)/3) \\ Charles R Greathouse IV, Jun 13 2017

A276353 Numbers k such that (19*10^k + 77) / 3 is prime.

Original entry on oeis.org

1, 2, 3, 5, 6, 17, 22, 56, 71, 90, 93, 109, 124, 135, 179, 255, 1804, 2541, 2707, 3195, 4952, 5884, 9301, 19847, 27903, 45739, 65545, 69424, 103907, 160619, 168173, 297497, 299640
Offset: 1

Views

Author

Robert Price, Aug 31 2016

Keywords

Comments

For k > 1, numbers k such that the digit 6 followed by k-2 occurrences of the digit 3 followed by the digits 59 is prime (see Example section).
a(34) > 3*10^5.

Examples

			3 is in this sequence because (19*10^3 + 77) / 3 = 6359 is prime.
Initial terms and associated primes:
a(1) = 1, 89;
a(2) = 2, 659
a(3) = 3, 6359;
a(4) = 5, 633359;
a(5) = 6, 6333359, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(19*10^# + 77) / 3] &]
  • PARI
    is(n)=ispseudoprime((19*10^n + 77)/3) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(29)-a(31) from Robert Price, May 28 2019
a(32)-a(33) from Robert Price, Jun 01 2023

A276470 Numbers k such that (25*10^k + 167) / 3 is prime.

Original entry on oeis.org

1, 3, 4, 5, 11, 15, 18, 37, 41, 58, 60, 87, 117, 118, 214, 265, 334, 355, 450, 655, 1695, 1734, 2183, 3913, 25313, 32865
Offset: 1

Views

Author

Robert Price, Sep 12 2016

Keywords

Comments

For k > 1, numbers k such that the digit 8 followed by k-2 occurrences of the digit 3 followed by the digits 89 is prime (see Example section).
a(27) > 2*10^5.

Examples

			3 is in this sequence because (25*10^3 + 167) / 3 = 8389 is prime.
Initial terms and associated primes:
a(1) = 1, 139;
a(2) = 3, 8389
a(3) = 4, 83389;
a(4) = 5, 833389;
a(5) = 11, 833333333389, etc.

Links

Crossrefs

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

Programs

  • Magma
    [n: n in [0..400] |IsPrime((25*10^n + 167) div 3)]; // Vincenzo Librandi, Sep 13 2016
  • Mathematica
    Select[Range[0, 100000], PrimeQ[(25*10^# + 167) / 3] &]
  • PARI
    is(n)=ispseudoprime((25*10^n + 167)/3) \\ Charles R Greathouse IV, Jun 13 2017

A276492 Numbers k such that 5*10^k + 59 is prime.

Original entry on oeis.org

1, 3, 7, 9, 10, 19, 21, 22, 43, 46, 58, 87, 216, 549, 604, 1147, 1858, 2952, 3684, 4057, 4246, 4354, 8212, 8289, 9013, 16968, 19107, 57754, 61348, 88254
Offset: 1

Views

Author

Robert Price, Sep 05 2016

Keywords

Comments

For k > 1, numbers k such that the digit 5 followed by k-2 occurrences of the digit 0 followed by the digits 59 is prime (see Example section).
a(31) > 2*10^5.

Examples

			3 is in this sequence because 5*10^3 + 59 = 5059 is prime.
Initial terms and associated primes:
a(1) = 1, 109;
a(2) = 3, 5059;
a(3) = 7, 50000059;
a(4) = 9, 5000000059;
a(5) = 10, 50000000059, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[5*10^# + 59] &]
  • PARI
    is(n)=ispseudoprime(5*10^n + 59) \\ Charles R Greathouse IV, Jun 13 2017

A276545 Numbers k such that (43*10^k - 421)/9 is prime.

Original entry on oeis.org

2, 5, 7, 8, 11, 13, 25, 26, 61, 82, 131, 289, 377, 547, 845, 929, 1786, 5887, 6562, 10546, 28033, 33493, 150515, 205183
Offset: 1

Views

Author

Robert Price, Apr 09 2017

Keywords

Comments

For k > 1, numbers k such that the digit 4 followed by k-2 occurrences of the digit 7 followed by the digits 31 is prime (see Example section).
a(25) > 3*10^5.

Examples

			4 is in this sequence because (43*10^4 - 421)/9 = 477731 is prime.
Initial terms and associated primes:
a(1) = 2, 431;
a(2) = 5, 477731;
a(3) = 7, 47777731;
a(4) = 8, 477777731;
a(5) = 11, 477777777731; etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[1, 100000], PrimeQ[(43*10^# - 421)/9] &]

Extensions

a(23) from Robert Price, Jan 21 2019
a(24) from Robert Price, Oct 25 2023

A276546 Numbers k such that (151*10^k - 1)/3 is prime.

Original entry on oeis.org

1, 3, 6, 15, 19, 34, 37, 88, 141, 216, 239, 246, 288, 365, 429, 762, 1879, 2309, 9555, 19843, 28348, 45058, 62879, 86963, 90669, 148020, 148601, 199003, 289877
Offset: 1

Views

Author

Robert Price, Apr 09 2017

Keywords

Comments

Numbers k such that the digits 50 followed by k occurrences of the digit 3 is prime (see Example section).
a(30) > 3*10^5.

Examples

			3 is in this sequence because (151*10^3 - 1)/3 = 50333 is prime.
Initial terms and associated primes:
a(1) = 1, 503;
a(2) = 3, 50333;
a(3) = 6, 50333333;
a(4) = 15, 50333333333333333;
a(5) = 19, 503333333333333333333; etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(151*10^# - 1)/3] &]

Extensions

a(26)-a(28) from Robert Price, Mar 17 2020
a(29) from Robert Price, Oct 25 2023

A276642 Numbers k such that 3*10^k + 89 is prime.

Original entry on oeis.org

2, 3, 4, 5, 6, 8, 10, 14, 15, 62, 98, 184, 190, 389, 430, 815, 918, 1124, 1284, 9544, 10068, 16514, 24756, 39880, 86478, 179138
Offset: 1

Views

Author

Robert Price, Mar 23 2017

Keywords

Comments

For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 0 followed by the digits 89 is prime (see Example section).
a(27) > 2*10^5.

Examples

			3 is in this sequence because 3*10^3 + 89 = 3089 is prime.
Initial terms and associated primes:
a(1) = 2, 389;
a(2) = 3, 3089;
a(3) = 4, 30089;
a(4) = 5, 300089;
a(5) = 6, 3000089; etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[3*10^# + 89] &]
  • PARI
    isok(k) = ispseudoprime(3*10^k + 89); \\ Altug Alkan, Mar 30 2018

Extensions

a(26) from Robert Price, Oct 22 2018
Previous Showing 101-110 of 498 results. Next

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