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.

A103401 Numbers k such that k211 is prime.

Original entry on oeis.org

0, 4, 6, 7, 10, 12, 18, 19, 21, 27, 28, 30, 33, 34, 49, 58, 61, 63, 67, 72, 75, 84, 87, 88, 96, 105, 108, 109, 111, 115, 118, 126, 130, 135, 142, 147, 150, 154, 157, 163, 165, 168, 175, 177, 180, 181, 184, 186, 187, 199, 201, 205, 214, 216, 223, 228, 234, 235, 249, 256, 258, 259, 264, 268, 271, 279
Offset: 1

Views

Author

Parthasarathy Nambi, Mar 20 2005

Keywords

Comments

Also numbers k such that 1000*k+211 is prime. - Stefan Steinerberger, Feb 12 2006

Examples

			If k=27, then k211 = 27211 (prime).
If k=72, then k211 = 72211 (prime).

Links

Crossrefs

Cf. A103118, A102624.

Programs

  • Magma
    [ n: n in [0..700] | IsPrime(Seqint([1, 1, 2] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 03 2011
  • Mathematica
    For[n = 0, n < 220, n++, If[PrimeQ[1000*n + 211], Print[n]]] (* Stefan Steinerberger, Feb 12 2006 *)
Select[Range[0,300],PrimeQ[1000#+211]&] (* Harvey P. Dale, Dec 14 2021 *)

Extensions

More terms from Stefan Steinerberger, Feb 12 2006

A102624 Numbers k such that the number k23 is prime.

Original entry on oeis.org

0, 2, 5, 8, 11, 12, 14, 15, 17, 18, 24, 30, 33, 36, 38, 39, 44, 45, 47, 50, 53, 56, 59, 63, 68, 75, 77, 78, 81, 84, 86, 89, 93, 96, 99, 102, 107, 114, 119, 123, 128, 129, 135, 137, 143, 144, 147, 149, 158, 159, 162, 168, 171, 176, 179, 182, 185, 194, 200, 201, 203, 210
Offset: 1

Views

Author

Parthasarathy Nambi, Jan 31 2005

Keywords

Examples

			If k=2, then k23 = 223 (prime).
If k=45, then k23 = 4523 (prime).
If k=99, then k23 = 9923 (prime).

Links

Crossrefs

Cf. A103401, A103408, A103118.

Programs

  • Magma
    [ n: n in [1..700] | IsPrime(Seqint([3,2] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011; misses the zero
  • Mathematica
    Select[Range[0,300],PrimeQ[100#+23]&] (* Harvey P. Dale, Apr 08 2019 *)
  • PARI
    is(n)=isprime(100*n+23) \\ Charles R Greathouse IV, Jun 06 2017

Extensions

More terms from Robert G. Wilson v, Feb 04 2005

A103408 Numbers n such that n2101 is prime.

Original entry on oeis.org

1, 4, 7, 10, 18, 24, 25, 28, 31, 34, 39, 42, 48, 51, 63, 70, 73, 76, 79, 81, 85, 93, 94, 100, 126, 139, 148, 150, 156, 157, 160, 163, 168, 174, 177, 184, 186, 199, 202, 207, 219, 232, 234, 235, 237, 265, 268, 277, 300, 301, 307, 309, 315, 316, 321, 322, 328, 343, 354, 358, 364, 366
Offset: 1

Views

Author

Parthasarathy Nambi, Mar 20 2005

Keywords

Examples

			If n=1, then n2101 = 12101 (prime).
If n=31, then n2101 = 312101 (prime).
If n=63, then n2101 = 632101 (prime).

Links

Crossrefs

Cf. A103118, A102624.

Programs

A103188 Numbers k such that k711 is prime.

Original entry on oeis.org

2, 5, 10, 13, 26, 28, 38, 43, 44, 47, 49, 52, 55, 56, 58, 68, 71, 77, 85, 86, 91, 97, 98, 104, 110, 121, 125, 127, 131, 133, 136, 142, 143, 148, 149, 160, 167, 170, 176, 181, 182, 184, 185, 187, 188, 190, 197, 211, 218, 223, 224, 229, 232, 239, 241, 244, 245, 247, 257, 265
Offset: 1

Views

Author

Parthasarathy Nambi, Mar 18 2005

Keywords

Examples

			If k=2, then k711 = 2711 (prime).
If k=43, then k711 = 43711 (prime).
If k=58, then k711 = 58711 (prime).

Links

Crossrefs

Cf. A103118.

Programs

  • Magma
    [ n: n in [1..700] | IsPrime(Seqint([1, 1, 7] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 03 2011
  • Mathematica
    Select[Range[300],PrimeQ[1000#+711]&] (* Harvey P. Dale, Jul 21 2016 *)

A141493 Ordered different numbers in A141425=b(n) and differences.

Original entry on oeis.org

1, 2, 4, 5, 7, 8, 16, 22, 23, 28, 29, 46, 74, 103
Offset: 0

Views

Author

Paul Curtz, Aug 10 2008

Keywords

Comments

First six numbers of a(n) and b(n) are the same.

Crossrefs

Cf. A103118.
Showing 1-5 of 5 results.

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