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 1-10 of 10 results.

A067200 Numbers m such that m^3 + 2 is prime.

Original entry on oeis.org

0, 1, 3, 5, 29, 45, 63, 65, 69, 71, 83, 105, 113, 123, 129, 143, 153, 171, 173, 189, 209, 215, 219, 231, 243, 245, 249, 263, 291, 299, 305, 311, 341, 363, 369, 395, 419, 425, 431, 435, 473, 483, 491, 495, 501, 503, 509, 515, 533, 549, 555, 561, 575, 579, 639
Offset: 1

Views

Author

Benoit Cloitre, Feb 19 2002

Keywords

Crossrefs

Cf. A144953.
Other sequences of the type "Numbers m such that m^k + k - 1 is prime": A000040 (k=1), A005574 (k=2), this sequence (k=3), A125259 (k=4), A125260 (k=5), A125261 (k=6), A125262 (k=7), A125263 (k=8), A125264 (k=10), A125265 (k=11).

Programs

Formula

a(n) = (A144953(n) - 2)^(1/3). - Zak Seidov, Sep 16 2013

A125259 Numbers k such that k^4 + 3 is prime.

Original entry on oeis.org

0, 2, 8, 16, 22, 26, 28, 34, 44, 62, 68, 76, 82, 92, 104, 110, 118, 128, 134, 166, 184, 202, 212, 266, 286, 296, 314, 328, 350, 356, 376, 406, 428, 436, 460, 470, 506, 520, 532, 562, 580, 638, 650, 652, 680, 692, 722, 734, 740, 778, 812, 820, 824, 862, 896, 908
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), this sequence (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10), A125265 (j=11)...

Programs

  • Mathematica
    Select[Range[0,1000],PrimeQ[#^4+3]&] (* Harvey P. Dale, Aug 02 2023 *)
  • PARI
    isok(n, k=4) = isprime(n^k + k - 1); \\ Michel Marcus, Oct 11 2013

A125265 Numbers k such that k^11 + 10 is prime.

Original entry on oeis.org

1, 7, 19, 21, 33, 69, 153, 157, 193, 253, 379, 391, 439, 543, 549, 559, 579, 609, 879, 937, 939, 993, 1063, 1083, 1107, 1119, 1191, 1209, 1267, 1281, 1287, 1333, 1537, 1617, 1797, 1819, 1923, 1971, 1987, 1989, 2041, 2061, 2073, 2101, 2103, 2343, 2373
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10).

Programs

A125261 Numbers k such that k^6 + 5 is prime.

Original entry on oeis.org

0, 18, 24, 114, 204, 216, 222, 246, 276, 312, 318, 372, 384, 426, 438, 468, 498, 582, 618, 654, 822, 888, 948, 984, 1182, 1188, 1272, 1278, 1284, 1374, 1446, 1536, 1674, 1782, 1788, 1794, 1806, 1812, 1896, 2034, 2058, 2088, 2124, 2154, 2232, 2238, 2376
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), this sequence(j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10), A125265 (j=11)..

Programs

A125263 Numbers k such that k^8 + 7 is prime.

Original entry on oeis.org

0, 2, 4, 10, 66, 68, 86, 88, 134, 146, 200, 216, 250, 276, 306, 310, 410, 422, 472, 492, 506, 516, 538, 548, 550, 594, 638, 716, 746, 758, 862, 888, 942, 954, 964, 982, 992, 998, 1000, 1016, 1020, 1034, 1108, 1164, 1192, 1234, 1338, 1342, 1350, 1374, 1390
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), this sequence (j=8), A125264 (j=10), A125265 (j=11)...

Programs

A125264 Numbers k such that k^10 + 9 is prime.

Original entry on oeis.org

2, 8, 238, 310, 338, 442, 542, 688, 698, 872, 920, 1198, 1330, 1382, 1538, 1558, 1678, 1702, 1712, 1768, 1882, 2032, 2080, 2102, 2260, 2312, 2408, 2440, 2540, 2642, 3112, 3170, 3188, 3268, 3320, 3580, 3740, 3742, 3770, 3980, 4028, 4048, 4148, 4292, 4472
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), this sequence (j=10), A125265 (j=11).

Programs

A246519 Primes p such that 4+p, 4+p^2, 4+p^3 and 4+p^5 are all prime.

Original entry on oeis.org

7, 5503, 21013, 301123, 303613, 420037, 469363, 679153, 771427, 991957, 999667, 1524763, 1707367, 2030653, 2333083, 2540563, 2552713, 2710933, 3009967, 3378103, 3441817, 3592213, 4419937, 4704613, 4840723, 5177797, 5691547, 6227587, 6275887, 6395677, 6595597, 6597163
Offset: 1

Views

Author

Zak Seidov, Aug 28 2014

Keywords

Comments

For even k > 2, 4 + n^k is prime only for n = 1.
From Derek Orr, Aug 28 2014 (edited by Danny Rorabaugh, Apr 19 2015): (Start)
4+p^4 is composite for all primes p. For p = 2, 4+p^4 = 20 is composite. To prove it for odd primes, consider S(n) = 4+(2*n+1)^4. S(n) == 0 (mod 5) unless n == 2 (mod 5). If n == 2 (mod 5), then 2*n+1 == 0 (mod 5), which is only prime for n = 2; this gives p = 5 and 4+5^4 = 629 is composite. For other odd primes p, 4+p^4 is greater than 5 and divisible by 5.
4+p^(4*m) is also composite for any prime p and integer m > 0. For each m, the proof is the same as above.
(End)
All terms are == {3,7} (mod 10). - Zak Seidov, Aug 29 2014

Examples

			From _K. D. Bajpai_, Jan 20 2015: (Start)
a(2) = 5503:
4 + 5503 = 5507;
4 + 5503^2 = 30283013;
4 + 5503^3 = 166647398531;
4 + 5503^5 = 5046584669419727747;
all five are prime.
(End)
		

Crossrefs

Primes p such that 4+p^7, 4+p^9 and 4+p^11 are also prime is A253937. - K. D. Bajpai, Jan 20 2015
The subsequence with 4+p^7 also prime is A246562. - Danny Rorabaugh, Apr 19 2015

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^7) | IsPrime(4+p) and IsPrime(4+p^2) and IsPrime(4+p^3) and IsPrime(4+p^5)]; // Vincenzo Librandi, Apr 19 2015
  • Mathematica
    k=4; Select[Prime[Range[1,500000]], PrimeQ[k+#]&&PrimeQ[k+#^2] &&PrimeQ[k+#^3] &&PrimeQ[k+#^5]&]  (*K. D. Bajpai, Jan 20 2015 *)
  • PARI
    for(n=1, 6000000, if(isprime(n) && isprime(4+n) && isprime(4+n^2) && isprime(4+n^3) && isprime(4+n^5), print1(n, ", "))) \\ Colin Barker, Aug 28 2014
    
  • PARI
    p=7; forprime(q=11, 1e8, if(q-p==4 && isprime(4+p^2) && isprime(4+p^3) && isprime(4+p^5), print1(p, ", ")); p=q) \\ Charles R Greathouse IV, Aug 28 2014
    
  • Python
    from sympy import prime, isprime
    A246519_list = [p for p in (prime(n) for n in range(1,10**5)) if all([isprime(4+p**z) for z in (1,2,3,5)])]
    # Chai Wah Wu, Sep 08 2014
    

A246562 Primes p such that 4+p, 4+p^2, 4+p^3, 4+p^5, and 4+p^7 are all prime.

Original entry on oeis.org

7, 469363, 2552713, 3378103, 6595597, 6629683, 39837517, 46024063, 46167307, 97371007, 97629403, 105528217, 136983307, 169483033, 202953613, 213792193, 216520987, 216738043, 221705647, 304033927, 317502193, 359133553
Offset: 1

Views

Author

Zak Seidov, Aug 29 2014

Keywords

Comments

All terms are == {3, 7} mod 10. Subsequence of A246519.

Crossrefs

Programs

  • Mathematica
    Select[Prime[Range[193*10^5]],AllTrue[#^{1,2,3,5,7}+4,PrimeQ]&] (* Harvey P. Dale, Sep 07 2024 *)
  • PARI
    forprime(p=1,10^9,if(ispseudoprime(4+p) && ispseudoprime(4+p^2) && ispseudoprime(4+p^3) && ispseudoprime(4+p^5) && ispseudoprime(4+p^7), print1(p,", "))) \\ Derek Orr, Aug 30 2014

A253937 Primes p such that 4+p^7, 4+p^9 and 4+p^11 are also prime.

Original entry on oeis.org

82609, 1032607, 1859479, 2158447, 4952173, 5009593, 5828353, 6779833, 11316859, 11370727, 12786157, 13872853, 14117053, 15082783, 15645697, 15935989, 16715623, 20102569, 21310603, 22106569, 22164253, 23674597, 26012953, 26325613, 29592919, 30086347, 30306637
Offset: 1

Views

Author

K. D. Bajpai, Jan 19 2015

Keywords

Examples

			a(1) = 82609:
4 + 82609^7 = 26253762656881427836948640304009173;
4 + 82609^9 = 179162157925737357103123335151825463343651893;
4 + 82609^11 = 1222646797417942588836172615268162579679296234658008213;
all four are prime.
		

Crossrefs

Programs

  • Mathematica
    Select[Prime[Range[1, 2000000]], PrimeQ[4 + #^7] && PrimeQ[4 + #^9] && PrimeQ[4 + #^11] &]
  • PARI
    forprime(p=1, 1e7, if(isprime(4+p^7) && isprime(4+p^9) && isprime(4+p^11), print1(p,", ")))

A243095 Least integer m > 1 such that 4 + m^n is prime or 1 if only 4 + 1^n is prime.

Original entry on oeis.org

3, 3, 3, 1, 7, 3, 7, 1, 3, 3, 9, 1, 33, 7, 9, 1, 43, 17, 27, 1, 9, 3, 7, 1, 55, 47, 285, 1, 27, 3, 39, 1, 43, 117, 163, 1, 63, 255, 15, 1, 87, 3, 43, 1, 187, 77, 37, 1, 105, 45, 25, 1, 99, 305, 79, 1, 3, 27, 903, 1, 127, 293, 255, 1, 27, 27, 435, 1, 207, 143, 127, 1, 117, 295, 1159, 1, 477
Offset: 1

Views

Author

Zak Seidov, Aug 29 2014

Keywords

Comments

If n is a multiple of 4 then 4 + m^n is prime iff m = 1.
4 + m^(4*x) = (m^(2*x)-2*m^x+2) * (m^(2*x)+2*m^x+2). - Jens Kruse Andersen, Sep 02 2014

Crossrefs

Programs

  • PARI
    a(n)=if(n%4==0,return(1));m=2;while(!ispseudoprime(4+m^n),m++);return(m)
    vector(100,n,a(n)) \\ Derek Orr, Aug 29 2014
Showing 1-10 of 10 results.