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 87 results. Next

A107152 Primes of the form x^2 + 45y^2.

Original entry on oeis.org

61, 109, 181, 229, 241, 349, 409, 421, 541, 601, 661, 709, 769, 829, 1009, 1021, 1069, 1129, 1201, 1249, 1321, 1381, 1429, 1489, 1549, 1609, 1621, 1669, 1741, 1789, 1801, 1861, 2029, 2089, 2161, 2221, 2269, 2281, 2341, 2389, 2521, 2689, 2749, 3001, 3049, 3061, 3109, 3121, 3169, 3181
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -180. See A107132 for more information.
Also primes of the form x^2 + 60y^2. See A140633. - T. D. Noe, May 19 2008
Also primes of the form x^2+6*x*y-6*y^2, of discriminant 60 (as well as of the form x^2+8*x*y+y^2). - Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 24 2008

References

  • Z. I. Borevich and I. R. Shafarevich, Number Theory.

Crossrefs

Cf. A139643.
Cf. A141302, A141303, A141304 (d=60).
All representatives in A243188.
For a list of sequences giving numbers and/or primes represented by binary quadratic forms, see the "Binary Quadratic Forms and OEIS" link.

Programs

  • Magma
    [ p: p in PrimesUpTo(3000) | p mod 60 in {1, 49 } ]; // Vincenzo Librandi, Jul 24 2012
    
  • Mathematica
    QuadPrimes2[1, 0, 45, 10000] (* see A106856 *)
    Select[Prime[Range[500]], MatchQ[Mod[#, 60], 1|49]&] (* Jean-François Alcover, Oct 28 2016 *)
  • PARI
    list(lim)=my(v=List(),t); forprime(p=61,lim, t=p%60; if(t==1||t==49, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

Primes congruent to {1, 49} (mod 60). - T. D. Noe, Apr 29 2008

A107145 Primes of the form x^2 + 40y^2.

Original entry on oeis.org

41, 89, 241, 281, 401, 409, 449, 521, 569, 601, 641, 761, 769, 809, 881, 929, 1009, 1049, 1129, 1201, 1249, 1289, 1321, 1361, 1409, 1481, 1489, 1601, 1609, 1721, 1801, 1889, 2081, 2089, 2129, 2161, 2281, 2441, 2521, 2609, 2689, 2729, 2801
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -160. See A107132 for more information.

Crossrefs

Cf. A139643.

Programs

  • Magma
    [ p: p in PrimesUpTo(3000) | p mod 40 in {1, 9} ]; // Vincenzo Librandi, Jul 24 2012
    
  • Mathematica
    QuadPrimes2[1, 0, 40, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List(),t); forprime(p=41,lim, t=p%40; if(t==1||t==9, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

The primes are congruent to {1, 9} (mod 40). - T. D. Noe, Apr 29 2008

A141373 Primes of the form 3*x^2+16*y^2. Also primes of the form 4*x^2+4*x*y-5*y^2 (as well as primes the form 4*x^2+12*x*y+3*y^2).

Original entry on oeis.org

3, 19, 43, 67, 139, 163, 211, 283, 307, 331, 379, 499, 523, 547, 571, 619, 643, 691, 739, 787, 811, 859, 883, 907, 1051, 1123, 1171, 1291, 1459, 1483, 1531, 1579, 1627, 1699, 1723, 1747, 1867, 1987, 2011, 2083, 2131, 2179, 2203, 2251, 2347, 2371, 2467, 2539
Offset: 1

Views

Author

T. D. Noe, May 13 2005; Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 28 2008

Keywords

Comments

The discriminant is -192 (or 96, or ...), depending on which quadratic form is used for the definition. Binary quadratic forms a*x^2+b*x*y+c*y^2 have discriminant d=b^2-4ac and gcd(a,b,c)=1. See A107132 for more information.
Except for 3, also primes of the forms 4x^2 + 4xy + 19y^2 and 16x^2 + 8xy + 19y^2. See A140633. - T. D. Noe, May 19 2008

Examples

			19 is a member because we can write 19=4*2^2+4*2*1-5*1^2 (or 19=4*1^2+12*1*1+3*1^2).
		

References

  • Z. I. Borevich and I. R. Shafarevich, Number Theory.

Crossrefs

See also A038872 (d=5),
A038873 (d=8),
A068228, A141123 (d=12),
A038883 (d=13),
A038889 (d=17),
A141158 (d=20),
A141159, A141160 (d=21),
A141170, A141171 (d=24),
A141172, A141173 (d=28),
A141174, A141175 (d=32),
A141176, A141177 (d=33),
A141178 (d=37),
A141179, A141180 (d=40),
A141181 (d=41),
A141182, A141183 (d=44),
A033212, A141785 (d=45),
A068228, A141187 (d=48),
A141188 (d=52),
A141189 (d=53),
A141190, A141191 (d=56),
A141192, A141193 (d=57),
A141215 (d=61),
A141111, A141112 (d=65),
A141336, A141337 (d=92),
A141338, A141339 (d=93),
A141161, A141163 (d=148),
A141165, A141166 (d=229),

Programs

  • Magma
    [3] cat [ p: p in PrimesUpTo(3000) | p mod 24 in {19 } ]; // Vincenzo Librandi, Jul 24 2012
    
  • Mathematica
    QuadPrimes2[3, 0, 16, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List(),w,t); for(x=1, sqrtint(lim\3), w=3*x^2; for(y=0, sqrtint((lim-w)\16), if(isprime(t=w+16*y^2), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

Except for 3, the primes are congruent to 19 (mod 24). - T. D. Noe, May 02 2008

Extensions

More terms from Colin Barker, Apr 05 2015
Edited by N. J. A. Sloane, Jul 14 2019, combining two identical entries both with multiple cross-references.

A107181 Primes of the form 8x^2 + 9y^2.

Original entry on oeis.org

17, 41, 89, 113, 137, 233, 257, 281, 353, 401, 449, 521, 569, 593, 617, 641, 761, 809, 857, 881, 929, 953, 977, 1049, 1097, 1193, 1217, 1289, 1361, 1409, 1433, 1481, 1553, 1601, 1697, 1721, 1889, 1913, 2081, 2129, 2153, 2273, 2297, 2393, 2417
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -288. See A107132 for more information.
Also primes of the form 9x^2 + 6xy + 17y^2. See A140633. - T. D. Noe, May 19 2008
All terms are of the form x^2 + y^2, see A002144. - Zak Seidov, Jan 26 2014

Crossrefs

Subsequence of A002144 (Pythagorean primes).
Cf. A139827.

Programs

  • Magma
    [ p: p in PrimesUpTo(5000) | p mod 24 eq 17 ]; // Vincenzo Librandi, Apr 19 2011
    
  • Mathematica
    QuadPrimes2[8, 0, 9, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List()); forprime(p=17,lim, if(p%24==17, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 10 2017

Formula

The primes are congruent to 17 (mod 24). - T. D. Noe, May 02 2008

A107169 Primes of the form 3x^2 + 20y^2.

Original entry on oeis.org

3, 23, 47, 83, 107, 167, 227, 263, 347, 383, 443, 467, 503, 563, 587, 647, 683, 743, 827, 863, 887, 947, 983, 1103, 1163, 1187, 1223, 1283, 1307, 1367, 1427, 1487, 1523, 1583, 1607, 1667, 1787, 1823, 1847, 1907, 2003, 2027, 2063, 2087, 2207
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -240. See A107132 for more information.
Except for 3, also primes of the forms 2x^2 + 2xy + 23y^2 (A139831) and 8x^2 + 4xy + 23y^2. See A140633. - T. D. Noe, May 19 2008

Crossrefs

Cf. A139827.

Programs

  • Magma
    [3] cat [p: p in PrimesUpTo(3000) | p mod 60 in [23, 47]]; // Vincenzo Librandi, Jul 25 2012
    
  • Mathematica
    QuadPrimes2[3, 0, 20, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List([3]),t); forprime(p=23,lim, t=p%60; if(t==23||t==47, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 10 2017

Formula

Except for 3, the primes are congruent to {23, 47} (mod 60). - T. D. Noe, May 02 2008

A107135 Primes of the form 5x^2 + 6y^2.

Original entry on oeis.org

5, 11, 29, 59, 101, 131, 149, 179, 251, 269, 389, 419, 461, 491, 509, 659, 701, 821, 941, 971, 1019, 1061, 1091, 1109, 1181, 1229, 1259, 1301, 1451, 1499, 1571, 1619, 1709, 1811, 1901, 1931, 1949, 1979, 2069, 2099, 2141, 2309, 2339, 2381, 2411
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -120. See A107132 for more information.
Except for 5, also primes of the form 11x^2 + 4xy + 14y^2. See A140633. - T. D. Noe, May 19 2008

Crossrefs

Cf. A139827.

Programs

  • Magma
    [ p: p in PrimesUpTo(3000) | p mod 120 in {5, 11, 29, 59, 101} ]; // Vincenzo Librandi, Jul 23 2012
    
  • Mathematica
    QuadPrimes2[5, 0, 6, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List([5]),s=[11,29,59,101]); forprime(p=11,lim, if(setsearch(s,p%120), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

The primes are congruent to {5, 11, 29, 59, 101} (mod 120). - T. D. Noe, May 02 2008

A107141 Primes of the form 4x^2 + 9y^2.

Original entry on oeis.org

13, 73, 97, 109, 181, 229, 241, 277, 337, 409, 421, 457, 541, 709, 733, 757, 829, 1009, 1033, 1093, 1117, 1129, 1153, 1213, 1237, 1249, 1381, 1453, 1489, 1597, 1609, 1621, 1669, 1753, 1777, 1873, 2017, 2029, 2089, 2113, 2161, 2221, 2281
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -144. See A107132 for more information.
These appear to be the same as Glaisher's 1889 list of primes == 1 mod 12 that have "negative character". - N. J. A. Sloane, Jul 30 2015

References

  • J. W. L. Glaisher, On the square of Euler's series, Proc. London Math. Soc., 21 (1889), 182-194.

Programs

  • Mathematica
    QuadPrimes2[4, 0, 9, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List(),w,t); for(x=1, sqrtint(lim\4), w=4*x^2; for(y=1, sqrtint((lim-w)\9), if(isprime(t=w+9*y^2), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017

A107144 Primes of the form 5x^2 + 8y^2.

Original entry on oeis.org

5, 13, 37, 53, 157, 173, 197, 277, 293, 317, 373, 397, 557, 613, 653, 677, 733, 757, 773, 797, 853, 877, 997, 1013, 1093, 1117, 1213, 1237, 1277, 1373, 1453, 1493, 1597, 1613, 1637, 1693, 1733, 1877, 1933, 1973, 1997, 2053, 2213, 2237, 2293
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -160. See A107132 for more information.
Except for 5, also primes of the form 13x^2 + 8xy + 32y^2. See A140633. - T. D. Noe, May 19 2008

Crossrefs

Cf. A139827.

Programs

  • Magma
    [5] cat [ p: p in PrimesUpTo(3000) | p mod 40 in {13, 37} ]; // Vincenzo Librandi, Jul 24 2012
    
  • Mathematica
    QuadPrimes2[5, 0, 8, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List([5]),t); forprime(p=13,lim, t=p%40; if(t==13||t==37, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

Except for 5, the primes are congruent to {13, 37} (mod 40). - T. D. Noe, May 02 2008

A107151 Primes of the form 5x^2 + 9y^2.

Original entry on oeis.org

5, 29, 41, 89, 101, 149, 269, 281, 389, 401, 449, 461, 509, 521, 569, 641, 701, 761, 809, 821, 881, 929, 941, 1049, 1061, 1109, 1181, 1229, 1289, 1301, 1361, 1409, 1481, 1601, 1709, 1721, 1889, 1901, 1949, 2069, 2081, 2129, 2141, 2309, 2381
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -180. See A107132 for more information.
Except for 5, also primes of the form 9x^2 + 6xy + 26y^2. See A140633. - T. D. Noe, May 19 2008

Crossrefs

Cf. A139827.

Programs

  • Magma
    [5] cat [ p: p in PrimesUpTo(3000) | p mod 60 in {29, 41 } ]; // Vincenzo Librandi, Jul 24 2012
    
  • Mathematica
    QuadPrimes2[5, 0, 9, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List([5]),t); forprime(p=29,lim, t=p%60; if(t==29||t==41, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 09 2017

Formula

Except for 5, the primes are congruent to {29, 41} (mod 60). - T. D. Noe, May 02 2008

A107159 Primes of the form 4x^2 + 13y^2.

Original entry on oeis.org

13, 17, 29, 113, 157, 181, 269, 313, 337, 373, 389, 521, 601, 641, 653, 673, 701, 797, 809, 1069, 1109, 1117, 1153, 1213, 1249, 1453, 1481, 1609, 1613, 1621, 1637, 1777, 1933, 1949, 1973, 2053, 2081, 2089, 2129, 2213, 2237, 2297, 2341, 2357, 2393
Offset: 1

Views

Author

T. D. Noe, May 13 2005

Keywords

Comments

Discriminant = -208. See A107132 for more information.

Programs

  • Mathematica
    QuadPrimes2[4, 0, 13, 10000] (* see A106856 *)
  • PARI
    list(lim)=my(v=List(),w,t); for(x=0, sqrtint(lim\4), w=4*x^2; for(y=1, sqrtint((lim-w)\13), if(isprime(t=w+13*y^2), listput(v,t)))); Set(v) \\ Charles R Greathouse IV, Feb 09 2017
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