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.

A064217 Least k such that k*7^n +/- 1 are twin primes.

Original entry on oeis.org

4, 6, 18, 24, 138, 60, 150, 720, 150, 234, 138, 966, 138, 420, 60, 1584, 420, 60, 1830, 1134, 162, 1080, 1482, 684, 240, 10074, 3378, 3300, 2742, 984, 2400, 4050, 5262, 3510, 3378, 960, 3612, 516, 6840, 6474, 4680, 4950, 12612, 7986, 4290, 8046, 5208
Offset: 0

Views

Author

Robert G. Wilson v, Sep 21 2001

Keywords

Crossrefs

Cf. A063983, A064213, A064214, A064215, A064218, A064220, A064221.

Programs

  • Mathematica
    Do[ k = 1; While[ ! PrimeQ[ k*7^n + 1 ] || ! PrimeQ[ k*7^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]

Extensions

Offset corrected by Georg Fischer, May 01 2022

A064218 Least k such that k*10^n +/- 1 are twin primes.

Original entry on oeis.org

4, 3, 6, 3, 18, 240, 24, 3, 174, 93, 57, 141, 465, 501, 105, 822, 552, 324, 555, 237, 867, 1488, 543, 2556, 1050, 105, 51, 429, 1470, 147, 567, 1329, 636, 5016, 645, 4713, 1116, 1029, 462, 567, 5757, 951, 5547, 1245, 2823, 5931, 1989, 525, 6246, 1716
Offset: 0

Views

Author

Robert G. Wilson v, Sep 21 2001

Keywords

Crossrefs

Cf. A063983, A064213, A064214, A064215, A064217, A064220, A064221.

Programs

  • Mathematica
    Do[ k = 1; While[ ! PrimeQ[ k*10^n + 1 ] || ! PrimeQ[ k*10^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]

Extensions

Offset corrected by Georg Fischer, May 01 2022

A064220 Least k such that k*11^n +/- 1 are twin primes.

Original entry on oeis.org

4, 18, 12, 12, 120, 168, 72, 78, 810, 312, 90, 138, 270, 948, 408, 192, 960, 1920, 738, 4698, 810, 1872, 6978, 2058, 3222, 570, 870, 390, 9708, 14118, 9378, 6822, 8730, 2250, 1008, 8052, 732, 5400, 2910, 5982, 2688, 16758, 1908, 258, 762, 1488, 12678
Offset: 0

Views

Author

Robert G. Wilson v, Sep 21 2001

Keywords

Crossrefs

Cf. A063983, A064213, A064214, A064215. A064217, A064218, A064221.

Programs

  • Mathematica
    Do[ k = 1; While[ ! PrimeQ[ k*11^n + 1 ] || ! PrimeQ[ k*11^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]
lk[n_]:=Module[{c=11^n,k=1},While[!PrimeQ[k*c+1]||!PrimeQ[k*c-1],k++];k]; Array[lk,50,0] (* Harvey P. Dale, Jun 15 2019 *)

Extensions

Offset corrected by Georg Fischer, May 01 2022

A064221 Least k such that k*12^n +/- 1 are twin primes.

Original entry on oeis.org

4, 1, 3, 19, 33, 4, 165, 35, 150, 35, 205, 35, 63, 435, 48, 4, 223, 399, 388, 149, 125, 86, 335, 491, 565, 876, 73, 250, 85, 526, 217, 139, 557, 676, 488, 629, 592, 1290, 2110, 366, 140, 2461, 6198, 6476, 2033, 751, 7258, 2054, 2275, 1345, 445
Offset: 0

Views

Author

Robert G. Wilson v, Sep 21 2001

Keywords

Crossrefs

Cf. A063983, A064213, A064214, A064215, A064217, A064218, A064220.

Programs

  • Mathematica
    Do[ k = 1; While[ ! PrimeQ[ k*12^n + 1 ] || ! PrimeQ[ k*12^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]
lktpQ[n_]:=Module[{c=12^n,k=1},While[!AllTrue[k*c+{1,-1},PrimeQ],k++];k]; Array[lktpQ,60,0] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 21 2015 *)

Extensions

Offset corrected by Georg Fischer, May 01 2022

A225057 Least prime p such that p*6^n +/- 1 are primes.

Original entry on oeis.org

2, 2, 2, 2, 47, 3, 53, 677, 823, 227, 1907, 1103, 17, 163, 2693, 1213, 277, 2767, 887, 8353, 1013, 773, 6967, 1423, 2593, 9643, 157, 18013, 263, 2137, 2837, 107, 3467, 2137, 17, 2777, 1453, 2683, 7963, 3517, 2767, 53527, 8563, 227, 367, 27673, 30853, 5087, 7723, 14753, 41687, 137, 48647, 26357, 16747, 2797, 9887, 35933
Offset: 1

Views

Author

Zak Seidov, Apr 26 2013

Keywords

Comments

a(1) >= A064215(n). First n's such that a(n) = A064215(n): 2, 3, 4, 6, 13, 27, 29, 32, 35, 40, 44, 45, 52, 60, 67, 71, 79, 86, 87, 97, 99.
According to Dickson's Conjecture a(n) exists for any n.

Links

Crossrefs

Cf. A064215 (least k: k*6^n +/- 1 are primes).

Programs

  • Mathematica
    Table[ n6=6^n; p = 2; While[ ! PrimeQ[q = p*n6 + 1 ] || ! PrimeQ[ q - 2 ], p = NextPrime[p] ]; p, {n, 100}]
Showing 1-5 of 5 results.

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

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