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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A272285 Primes of the form 43*n^2 - 537*n + 2971 in order of increasing nonnegative values of n.

Original entry on oeis.org

2971, 2477, 2069, 1747, 1511, 1361, 1297, 1319, 1427, 1621, 1901, 2267, 2719, 3257, 3881, 4591, 5387, 6269, 7237, 8291, 9431, 10657, 11969, 13367, 14851, 16421, 18077, 19819, 21647, 23561, 25561, 27647, 29819, 32077, 34421, 39367, 41969, 44657, 47431, 50291
Offset: 1

Views

Author

Robert Price, Apr 24 2016

Keywords

Examples

			1511 is in this sequence since 43*4^2 - 537*4 + 2971 = 688-2148+2971 = 1511 is prime.
		

Crossrefs

Programs

  • Mathematica
    n = Range[0, 100]; Select[43n^2 - 537n + 2971, PrimeQ[#] &]
  • PARI
    lista(nn) = for(n=0, nn, if(ispseudoprime(p=43*n^2 - 537*n + 2971), print1(p, ", "))); \\ Altug Alkan, Apr 24 2016

A331940 Addends k > 0 such that the polynomial x^2 + x + k produces a record of its Hardy-Littlewood Constant.

Original entry on oeis.org

1, 11, 17, 41, 21377, 27941, 41537, 55661, 115721, 239621, 247757
Offset: 1

Views

Author

Hugo Pfoertner, Feb 02 2020

Keywords

Comments

The Hardy and Littlewood Conjecture F provides an estimate of the number of primes generated by a quadratic polynomial P(x) for 0 <= x <= m in the form C * Integral_{x=2..m} 1/log(x) dx, with C given by an Euler product that is a function of the fundamental discriminant of the polynomial. Cohen describes an efficient method for the computation of C.
The following table provides the record values of C, together with the number of primes np generated by the polynomial x^2 + x + a(n) for x <= 10^8 and the actual ratio 2*np/Integral_{x=2..10^8} 1/log(x) dx.
a(n) C np C from ratio
1 2.24147 6456835 2.24110
11 3.25944 9389795 3.25910
17 4.17466 12027453 4.17460
41 6.63955 19132653 6.64073
21377 6.92868 19962992 6.92894
27941 7.26400 20931145 7.26497
41537 7.32220 21092134 7.32085
55661 7.45791 21483365 7.45664
115721 7.70935 22210771 7.70912
239621 7.72932 22268336 7.72909
247757 8.24741 23762118 8.24757
Jacobson and Williams found significantly larger values of C for very large addends k, e.g. C = 2*5.36708 = 10.73416 for k = 3399714628553118047.

References

  • Keith Conrad, Hardy-Littlewood Constants. In: Mathematical Properties of Sequences and Other Combinatorial Structures, eds. Jong-Seon No, Hong-Yeop Song, Tor Helleseth, P. Vijay Kumar, Springer New York, 2003, pages 133-154.

Crossrefs

Cf. A221712, A221713 (Constants C including factor 1/2).

Programs

  • PARI
    \\ The function HardyLittlewood2 is provided at the Belabas, Cohen link.
    hl2max=0; for(add=0,100,my(hl=HardyLittlewood2(n^2+n+add)); if(hl>hl2max,print1(add,", "); hl2max=hl))

A272284 Numbers n such that 43*n^2 - 537*n + 2971 is prime.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 42, 43, 44, 45, 46, 47, 49, 50, 51, 55, 56, 57, 60, 64, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 79, 80, 81
Offset: 1

Views

Author

Robert Price, Apr 24 2016

Keywords

Comments

35 is the smallest number not in this sequence.

Examples

			4 is in this sequence since 43*4^2 - 537*4 + 2971 = 688-2148+2971 = 1511 is prime.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[0, 100], PrimeQ[43#^2 - 537# + 2971] &]
  • PARI
    lista(nn) = for(n=0, nn, if(ispseudoprime(43*n^2 - 537*n + 2971), print1(n, ", "))); \\ Altug Alkan, Apr 24 2016

A272401 Primes of the form abs(3n^3 - 183n^2 + 3318n - 18757) in order of increasing nonnegative n.

Original entry on oeis.org

18757, 15619, 12829, 10369, 8221, 6367, 4789, 3469, 2389, 1531, 877, 409, 109, 41, 59, 37, 229, 499, 829, 1201, 1597, 1999, 2389, 2749, 3061, 3307, 3469, 3529, 3469, 3271, 2917, 2389, 1669, 739, 419, 1823, 3491, 5441, 7691, 10259, 13163, 16421, 20051, 24071
Offset: 1

Views

Author

Robert Price, Apr 28 2016

Keywords

Examples

			8221 is in this sequence since abs(3*4^3 - 183*4^2 + 3318*4 - 18757) = abs(192-2928+13272-18757) = 8221 is prime.
		

Crossrefs

Programs

  • Mathematica
    n = Range[0, 100]; Select[3n^3 - 183n^2 + 3318n - 18757 , PrimeQ[#] &]

A117530 Triangle read by rows: T(n,k) = k^2 - k + prime(n), 1<=k<=n.

Original entry on oeis.org

2, 3, 5, 5, 7, 11, 7, 9, 13, 19, 11, 13, 17, 23, 31, 13, 15, 19, 25, 33, 43, 17, 19, 23, 29, 37, 47, 59, 19, 21, 25, 31, 39, 49, 61, 75, 23, 25, 29, 35, 43, 53, 65, 79, 95, 29, 31, 35, 41, 49, 59, 71, 85, 101, 119, 31, 33, 37, 43, 51, 61, 73, 87, 103, 121, 141, 37, 39, 43, 49, 57
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 25 2006

Keywords

Comments

A117531 gives the number of primes in the n-th row;
if T(n,1) is a Lucky Number of Euler then A117531(n)=n, see A014556.

Examples

			T(5,k)=A048058(k)=A048059(k), 1<=k<=5: T(5,1)=A014556(4)=11;
T(7,k)=A007635(k), 1<=k<=7: T(7,1)=A014556(5)=17;
T(13,k)=A005846(k), 1<=k<=13: T(13,1)=A014556(6)=41.
		

Crossrefs

Programs

Formula

T(n,1) = A000040(k).
T(n,2) = A052147(k) for k>1.
For 1

A272118 Numbers k such that abs(6*k^2 - 342*k + 4903) is prime.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 61, 62, 64, 66, 67, 68, 69, 71, 72
Offset: 1

Author

Robert Price, Apr 20 2016

Keywords

Examples

			4 is in this sequence since 6*4^2 - 342*4 + 4903 = 96-1368+4903 = 3631 is prime.
		

Programs

  • Mathematica
    Select[Range[0, 100], PrimeQ[6*#^2 - 342*# + 4903] &]
  • PARI
    isok(n) = isprime(abs(6*n^2 - 342*n + 4903)); \\ Michel Marcus, Apr 21 2016

A272302 Nonnegative numbers n such that abs(3n^3 - 183n^2 + 3318n - 18757) is prime.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 49, 51, 53, 56, 57, 59, 60, 62, 63, 65, 66, 69, 70, 74, 79, 80, 81, 82, 85
Offset: 1

Author

Robert Price, Apr 28 2016

Keywords

Comments

47 is the smallest number not in this sequence.

Examples

			4 is in this sequence since abs(3*4^3 - 183*4^2 + 3318*4 - 18757) = abs(192-2928+13272-18757) = 8221 is prime.
		

Programs

  • Mathematica
    Select[Range[0, 100], PrimeQ[3#^3 - 183#^2 + 3318# - 18757 ] &]
  • PARI
    is(n)=isprime(abs(3*n^2-183*n^2+3318*n-18757)) \\ Charles R Greathouse IV, Feb 17 2017

A272438 Primes of the form abs(-66n^3 + 3845n^2 - 60897n + 251831) in order of increasing nonnegative n.

Original entry on oeis.org

251831, 194713, 144889, 101963, 65539, 35221, 10613, 8681, 23057, 32911, 38639, 40637, 39301, 35027, 28211, 19249, 8537, 3529, 16553, 30139, 43891, 57413, 70309, 82183, 92639, 101281, 107713, 111539, 112363, 109789, 103421, 92863, 77719, 57593, 32089, 811
Offset: 1

Author

Robert Price, Apr 29 2016

Keywords

Examples

			65539 is in this sequence since abs(-66*4^3 + 3845*4^2 - 60897*4 + 251831) = abs(-4224+61520-243588+251831) = 65539 is prime.
		

Programs

  • Mathematica
    n = Range[0, 100]; Select[-66n^3 + 3845n^2 - 60897n + 251831, PrimeQ[#] &]

A272437 Nonnegative numbers n such that abs(-66n^3 + 3845n^2 - 60897n + 251831) is prime.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 47, 49, 51, 54, 58, 65, 68, 70, 75, 76, 77, 82, 88, 89, 97, 99, 101, 102, 104, 109
Offset: 1

Author

Robert Price, Apr 29 2016

Keywords

Comments

46 is the smallest number not in this sequence.

Examples

			4 is in this sequence since abs(-66*4^3 + 3845*4^2 - 60897*4 + 251831) = abs(-4224+61520-243588+251831) = 65539 is prime.
		

Programs

  • Mathematica
    Select[Range[0, 109], PrimeQ[-66#^3 + 3845#^2 - 60897# + 251831] &]
  • PARI
    is(n)=isprime(abs(66*n^3-3845*n^2+60897*n-251831)) \\ Charles R Greathouse IV, Feb 20 2017

A272444 Primes of the form abs(n^5 - 99n^4 + 3588n^3 - 56822n^2 + 348272n - 286397) in order of increasing nonnegative n.

Original entry on oeis.org

286397, 8543, 210011, 336121, 402851, 424163, 412123, 377021, 327491, 270631, 212123, 156353, 106531, 64811, 32411, 9733, 3517, 8209, 5669, 2441, 14243, 27763, 41051, 52301, 59971, 62903, 60443, 52561, 39971, 24251, 7963, 5227, 10429, 1409, 29531, 91673
Offset: 1

Author

Robert Price, Apr 29 2016

Keywords

Examples

			402851 is in this sequence since abs(4^5 - 99*4^4 + 3588*4^3 - 56822*4^2 + 348272*4 - 286397) = abs(1024-25344+229632-909152+1393088-286397) = 402851 is prime.
		

Programs

  • Mathematica
    n = Range[0, 100]; Select[n^5 - 99n^4 + 3588n^3 - 56822n^2 + 348272n - 286397, PrimeQ[#] &]
  • PARI
    lista(nn) = for(n=0, nn, if(isprime(p=abs(n^5-99*n^4+3588*n^3-56822*n^2+348272*n-286397)), print1(p, ", "))); \\ Altug Alkan, Apr 29 2016
Previous Showing 11-20 of 55 results. Next