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 1-3 of 3 results.

A167442 Prime numbers ending in the prime number 11.

Original entry on oeis.org

11, 211, 311, 811, 911, 1511, 1811, 2011, 2111, 2311, 2411, 2711, 3011, 3511, 3911, 4111, 4211, 5011, 5711, 6011, 6211, 6311, 6911, 7211, 7411, 8011, 8111, 8311, 9011, 9311, 9511, 9811, 10111, 10211, 10711, 11311, 11411, 12011, 12211, 12511, 12611
Offset: 1

Views

Author

Mark A. Thomas, Nov 03 2009

Keywords

Comments

Also primes of the form 100*n+11. - Vincenzo Librandi, Jul 07 2014

Links

Crossrefs

Cf. A101471.
Cf. similar sequences listed in A244763.

Programs

  • Magma
    [n: n in PrimesUpTo(15000) | n mod 100 eq 11]; // Vincenzo Librandi, Jul 07 2014
  • Mathematica
    Select[Prime[Range[5, 6000]], Take[IntegerDigits[#], -2]=={1, 1} &] (* Vincenzo Librandi, Jul 07 2014 *)
Select[Range[11,20011,100],PrimeQ] (* Harvey P. Dale, Nov 09 2014 *)
  • PARI
    select(x->(x % 100)==11, primes(2000)) \\ Michel Marcus, Jul 07 2014

A102372 Numbers k such that k11111 is prime.

Original entry on oeis.org

3, 5, 6, 9, 20, 24, 26, 39, 42, 48, 60, 65, 68, 83, 84, 93, 95, 108, 119, 126, 132, 146, 167, 179, 182, 189, 203, 206, 213, 224, 227, 230, 233, 234, 249, 258, 269, 270, 272, 291, 296, 305, 315, 324, 329, 336, 341, 345, 347, 348, 363, 368, 377, 384, 387, 392, 402, 422, 423, 438, 440, 450, 455, 458
Offset: 1

Views

Author

Parthasarathy Nambi, Feb 22 2005

Keywords

Examples

			If k=3, then k11111 = 311111 (prime).
If k=60, then k11111 = 6011111 (prime).
If k=126, then k11111 = 12611111 (prime).

Crossrefs

Cf. A101471, A102248, A102249.

Programs

  • Magma
    [ n: n in [1..700] | IsPrime(Seqint([1,1,1,1,1] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011
  • Mathematica
    Select[Range[500],PrimeQ[100000#+11111]&] (* Harvey P. Dale, Jan 15 2013 *)

A104048 Numbers k such that k11 is prime and k is a multiple of ten.

Original entry on oeis.org

0, 20, 30, 50, 60, 80, 90, 120, 140, 170, 200, 210, 230, 270, 300, 360, 380, 410, 540, 590, 620, 650, 690, 710, 750, 840, 860, 870, 900, 980, 1080, 1130, 1200, 1220, 1260, 1290, 1310, 1460, 1470, 1490, 1500, 1560, 1620, 1640, 1770, 1820, 1880, 1890, 2010, 2030, 2100, 2220, 2240, 2270
Offset: 1

Views

Author

Parthasarathy Nambi, Mar 01 2005

Keywords

Examples

			20 is a term because it is a multiple of 10 and 2011 is a prime.
170 is a term because it is a multiple of 10 and 17011 is a prime.
360 is a term because it is a multiple of 10 and 36011 is a prime.

Crossrefs

Cf. A101471.

Programs

  • Mathematica
    Select[Range[0,2270,10],PrimeQ[FromDigits[Prepend[{1,1},#]]]&] (* James C. McMahon, Jan 20 2024 *)
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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