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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A275285 Numbers k such that 33*10^k + 7 is prime.

Original entry on oeis.org

1, 2, 5, 6, 30, 58, 66, 127, 138, 179, 287, 520, 767, 954, 966, 1254, 1313, 1976, 2266, 2496, 3137, 4058, 4411, 7009, 11736, 12155, 21328, 31124, 31589, 38581, 42683, 54634, 56634, 85297
Offset: 1

Views

Author

Robert Price, Jul 21 2016

Keywords

Comments

For k > 0, numbers k such that the digits 33 followed by k-1 occurrences of the digit 0 followed by the digit 7 is prime (see Example section).
a(35) > 10^5.

Examples

			5 is in this sequence because 33*10^5 + 7 = 3300007 is prime.
Initial terms and associated primes:
a(1) = 1, 337;
a(2) = 2, 3307;
a(3) = 5, 3300007;
a(4) = 6, 33000007;
a(5) = 30, 33000000000000000000000000000007, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[33*10^# + 7] &]
  • PARI
    lista(nn) = for(n=1, nn, if(ispseudoprime(33*10^n+7), print1(n, ", "))); \\ Altug Alkan, Jul 21 2016

A275287 Numbers k such that (26*10^k - 107)/9 is prime.

Original entry on oeis.org

1, 2, 5, 7, 13, 23, 25, 44, 110, 157, 751, 853, 964, 1135, 2588, 2602, 2807, 2888, 3272, 4046, 4798, 16720, 21410, 22285, 25888, 34586, 51764
Offset: 1

Views

Author

Robert Price, Jul 21 2016

Keywords

Comments

For k > 1, numbers k such that the digit 2 followed by k-2 occurrences of the digit 8 followed by the digits 77 is prime (see Example section).
a(28) > 10^5.

Examples

			5 is in this sequence because (26*10^5 - 107)/9 = 288877 is prime.
Initial terms and associated primes:
a(1) = 1, 17;
a(2) = 2, 277;
a(3) = 5, 288877;
a(4) = 7, 28888877;
a(5) = 13, 28888888888877, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(26*10^# - 107)/9] &]
  • PARI
    lista(nn) = for(n=1, nn, if(ispseudoprime((26*10^n-107)/9), print1(n, ", "))); \\ Altug Alkan, Jul 22 2016

A275323 Numbers k such that (19*10^k + 161)/9 is prime.

Original entry on oeis.org

2, 3, 5, 6, 8, 18, 36, 59, 80, 162, 197, 200, 405, 432, 930, 1065, 1496, 1716, 3213, 5712, 6303, 7466, 14150, 23685, 54608, 59766
Offset: 1

Views

Author

Robert Price, Jul 23 2016

Keywords

Comments

For k > 1, numbers k such that the digit 2 followed by k-2 occurrences of the digit 1 followed by the digits 29 is prime (see Example section).
a(27) > 10^5.

Examples

			5 is in this sequence because (19*10^5 + 161)/9 = 211129 is prime.
Initial terms and associated primes:
a(1) = 2, 229;
a(2) = 3, 2129;
a(3) = 5, 211129;
a(4) = 6, 2111129;
a(5) = 8, 211111129, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(19*10^# + 161)/9] &]
  • PARI
    is(n)=ispseudoprime((19*10^n+161)/9) \\ Charles R Greathouse IV, Jun 13 2017

A275410 Numbers k such that (493*10^k - 7)/9 is prime.

Original entry on oeis.org

1, 2, 5, 7, 8, 14, 19, 22, 23, 31, 62, 65, 79, 178, 356, 401, 517, 557, 1040, 2248, 6718, 10730, 15079, 24938, 36241, 58486, 69340
Offset: 1

Views

Author

Robert Price, Jul 26 2016

Keywords

Comments

Numbers k such that the digits 54 followed by k occurrences of the digit 7 is prime (see Example section).
a(28) > 10^5.

Examples

			5 is in this sequence because (493*10^5-7)/9 = 5477777 is prime.
Initial terms and associated primes:
a(1) = 1, 547;
a(2) = 2, 5477;
a(3) = 5, 5477777;
a(4) = 7, 547777777;
a(5) = 8, 5477777777, etc.

Links

Crossrefs

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

Programs

  • Magma
    [n: n in [0..500] | IsPrime((493*10^n-7) div 9)]; // Vincenzo Librandi, Jul 27 2016
  • Mathematica
    Select[Range[0, 100000], PrimeQ[(493*10^#-7)/9] &]
  • PARI
    is(n)=ispseudoprime((493*10^n-7)/9) \\ Charles R Greathouse IV, Jun 13 2017

A275522 Numbers k such that (28*10^k + 773)/9 is prime.

Original entry on oeis.org

0, 2, 5, 6, 11, 20, 32, 59, 81, 98, 128, 437, 758, 989, 998, 1403, 1548, 1907, 1914, 2219, 5414, 9047, 13196, 18518, 28382
Offset: 1

Views

Author

Robert Price, Jul 31 2016

Keywords

Comments

For k > 1, numbers k such that the digit 3 followed by k-2 occurrences of the digit 1 followed by the digits 97 is prime (see Example section).
a(26) > 10^5.

Examples

			5 is in this sequence because (28*10^5 + 773)/9 = 311197 is prime.
Initial terms and associated primes:
a(1) = 0, 89;
a(2) = 2, 397;
a(3) = 5, 311197;
a(4) = 6, 3111197;
a(5) = 11, 311111111197, etc.

Links

Crossrefs

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

Programs

  • Magma
    [n: n in [0..500] | IsPrime((28*10^n+773) div 9)]; // Vincenzo Librandi, Aug 01 2016
  • Mathematica
    Select[Range[0, 100000], PrimeQ[(28*10^# + 773)/9] &]
  • PARI
    is(n)=ispseudoprime((28*10^n+773)/9) \\ Charles R Greathouse IV, Jun 13 2017

A275523 Numbers k such that 2*10^k + 93 is prime.

Original entry on oeis.org

1, 2, 6, 7, 8, 11, 42, 73, 115, 131, 163, 178, 247, 320, 343, 346, 736, 1230, 1556, 3746, 5946, 6020, 6566, 6770, 11302, 14024, 29062, 33268, 37424, 42187, 49216, 51000, 79242, 81287
Offset: 1

Views

Author

Robert Price, Jul 31 2016

Keywords

Comments

For k > 1, numbers k such that the digit 2 followed by k-2 occurrences of the digit 0 followed by the digits 93 is prime (see Example section).
a(35) > 10^5.

Examples

			6 is in this sequence because 2*10^6 + 93 = 2000093 is prime.
Initial terms and associated primes:
a(1) = 1, 113;
a(2) = 2, 293;
a(3) = 6, 2000093;
a(4) = 7, 20000093;
a(5) = 8, 200000093, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[2*10^# + 93] &]
  • PARI
    is(n)=ispseudoprime(2*10^n+93) \\ Charles R Greathouse IV, Jun 13 2017

A275524 Numbers k such that (56*10^k + 223)/9 is prime.

Original entry on oeis.org

0, 2, 3, 5, 8, 32, 36, 53, 92, 126, 156, 158, 536, 639, 846, 1356, 1953, 2237, 4407, 5082, 17447, 17922, 24806, 25926, 29699, 30474, 37424, 63942
Offset: 1

Views

Author

Robert Price, Jul 31 2016

Keywords

Comments

For k > 1, numbers k such that the digit 6 followed by k-2 occurrences of the digit 2 followed by the digits 47 is prime (see Example section).
a(29) > 10^5.

Examples

			3 is in this sequence because (56*10^3 + 223)/9 = 6247 is prime.
Initial terms and associated primes:
a(1) = 0, 31;
a(2) = 2, 647;
a(3) = 3, 6247;
a(4) = 5, 622247;
a(5) = 8, 622222247, etc.

Links

Crossrefs

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

Programs

  • Magma
    [n: n in [0..500] | IsPrime((56*10^n+223) div 9)]; // Vincenzo Librandi, Aug 01 2016
  • Mathematica
    Select[Range[0, 100000], PrimeQ[(56*10^# + 223)/9] &]
  • PARI
    is(n)=ispseudoprime((56*10^n+223)/9) \\ Charles R Greathouse IV, Jun 13 2017

A275525 Numbers k such that (73*10^k + 107)/9 is prime.

Original entry on oeis.org

2, 3, 5, 6, 11, 12, 26, 32, 36, 75, 137, 143, 279, 290, 363, 716, 770, 1377, 1638, 4470, 5952, 10526, 15132, 27054, 81485
Offset: 1

Views

Author

Robert Price, Aug 11 2016

Keywords

Comments

For k > 1, numbers k such that the digit 8 followed by k-2 occurrences of the digit 1 followed by the digits 23 is prime (see Example section).
a(26) > 10^5.

Examples

			3 is in this sequence because (73*10^3+107)/9 = 8123 is prime.
Initial terms and associated primes:
a(1) = 2, 823;
a(2) = 3, 8123;
a(3) = 5, 811123;
a(4) = 6, 8111123;
a(5) = 11, 811111111123, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(73*10^#+107)/9] &]
  • PARI
    lista(nn) = for(n=1, nn, if(ispseudoprime((73*10^n+107)/9), print1(n, ", "))); \\ Altug Alkan, Aug 11 2016

A275538 Numbers k such that (38*10^k + 547)/9 is prime.

Original entry on oeis.org

1, 3, 4, 9, 10, 13, 19, 21, 25, 28, 70, 81, 97, 106, 291, 369, 460, 577, 4705, 5427, 7153, 7191, 7885, 12070, 20794, 34855
Offset: 1

Views

Author

Robert Price, Aug 01 2016

Keywords

Comments

For k > 1, numbers k such that the digit 4 followed by k-2 occurrences of the digit 2 followed by the digits 83 is prime (see Example section).
a(27) > 10^5.

Examples

			3 is in this sequence because (38*10^3 + 547)/9 = 4283 is prime.
Initial terms and associated primes:
a(1) = 1, 103;
a(2) = 3, 4283;
a(3) = 4, 42283;
a(4) = 9, 4222222283;
a(5) = 10, 42222222283, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(38*10^# + 547)/9] &]
  • PARI
    isok(n) = isprime((38*10^n + 547)/9); \\ Michel Marcus, Aug 01 2016

A275802 Numbers k such that (76*10^k + 167)/9 is prime.

Original entry on oeis.org

1, 2, 4, 5, 7, 10, 16, 19, 28, 37, 41, 44, 53, 311, 490, 1252, 4360, 4732, 5575, 6833, 8878, 11171, 11396, 13079, 14903, 76615
Offset: 1

Views

Author

Robert Price, Aug 09 2016

Keywords

Comments

For k > 1, numbers k such that the digit 8 followed by k-2 occurrences of the digit 4 followed by the digits 63 is prime (see Example section).
a(27) > 10^5.

Examples

			4 is in this sequence because (76*10^4+167)/9 = 84463 is prime.
Initial terms and associated primes:
a(1) = 1, 103;
a(2) = 2, 863;
a(3) = 4, 84463;
a(4) = 5, 844463;
a(5) = 7, 84444463, etc.

Links

Crossrefs

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

Programs

  • Mathematica
    Select[Range[0, 100000], PrimeQ[(76*10^#+167)/9] &]
  • PARI
    is(n)=ispseudoprime((76*10^n+167)/9) \\ Charles R Greathouse IV, Jun 13 2017
Previous Showing 81-90 of 490 results. Next

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