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.

Previous Showing 11-19 of 19 results.

A138923 Indices k such that A020506(k)=Phi[k](-7) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

3, 9, 10, 15, 17, 23, 25, 26, 27, 28, 29, 36, 42, 47, 48, 61, 76, 84, 110, 126, 148, 210, 224, 262, 280, 288, 296, 298, 325, 327, 332, 352, 365, 456, 513, 528, 740, 1062, 1162, 1445, 1460, 1518, 1619, 1660, 2094, 2130, 2260, 2380, 3398, 3447, 3918
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Comments

There are only 6 terms between 365 and 1445 (exclusive).

Crossrefs

Programs

  • Mathematica
    Select[ Range[ 2400], PrimeQ[ Cyclotomic[#, -7]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-7)) && print1( i",")) /* use ...subst(polcyclo(i),x,-7)... in PARI < 2.4.2 */

A138924 Indices k such that A020505(k)=Phi[k](-6) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

3, 4, 6, 8, 9, 11, 14, 15, 21, 24, 25, 31, 42, 43, 45, 47, 58, 59, 77, 107, 124, 142, 144, 177, 192, 254, 279, 360, 407, 437, 480, 525, 542, 551, 579, 764, 811, 822, 891, 917, 1018, 1028, 1150, 1326, 1376, 1464, 1468, 1650, 1719, 1924, 2096, 2098, 2176, 2226
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Select[ Range[ 2000], PrimeQ[ Cyclotomic[#, -6]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-6)) && print1( i",")) /* use ...subst(polcyclo(i),x,-6)... in PARI < 2.4.2 */

Extensions

a(51)-a(54) from Robert Price, Apr 02 2012

A138925 Indices k such that A020504(k)=Phi[k](-5) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

5, 6, 12, 14, 22, 24, 26, 28, 45, 48, 55, 56, 67, 88, 92, 94, 98, 99, 101, 103, 108, 114, 116, 120, 229, 236, 248, 254, 265, 282, 288, 298, 322, 347, 362, 384, 399, 420, 500, 536, 567, 615, 620, 714, 835, 992, 1047, 1064, 1238, 1794, 1858, 1962, 2313, 2397
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Select[ Range[ 2000], PrimeQ[ Cyclotomic[#, -5]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-5)) && print1( i",")) /* use ...subst(polcyclo(i),x,-5)... in PARI < 2.4.2 */

Extensions

a(53)-a(54) from Robert Price, Apr 05 2012

A138926 Indices k such that A020503(k)=Phi[k](-4) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

3, 4, 8, 12, 16, 20, 28, 40, 60, 92, 96, 104, 140, 148, 156, 300, 356, 408, 596, 612, 692, 732, 756, 800, 952, 996, 1004, 1228, 1268, 2240, 2532, 3060, 3796, 3824, 3944, 5096, 5540, 7476, 7700, 8544, 9800, 14628, 15828, 16908, 18480, 20260, 21924, 24656, 38456
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Comments

It appears that for all k>1, a(k) is a multiple of 4.
It also appears that all Cyclotomic Polynomials, Phi[k](x), where k is a multiple of 4 have no odd powers of x. For example, Phi[20](x)=x^8-x^6+x^4-x^2+1. This implies that Phi[k](x)=Phi[k](-x), where k is a multiple of 4. - Robert Price, Apr 14 2012

Crossrefs

Programs

  • Mathematica
    Select[ Range[3, 5000], PrimeQ[ Cyclotomic[#, -4]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-4)) && print1( i",")) /* use ...subst(polcyclo(i),x,-4)... in PARI < 2.4.2 */

Extensions

a(36)-a(49) from Robert Price, Apr 07 2012

A138927 Indices k such that A020502(k)=Phi[k](-3) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

3, 5, 6, 7, 12, 13, 14, 18, 23, 24, 26, 30, 35, 36, 40, 42, 43, 60, 65, 66, 72, 77, 108, 126, 132, 142, 206, 215, 236, 276, 281, 286, 290, 304, 322, 359, 364, 391, 464, 487, 510, 522, 528, 529, 535, 558, 574, 577, 672, 680, 713, 731, 760, 799, 828, 892, 984
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Select[ Range[3, 1000], PrimeQ[ Cyclotomic[#, -3]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-3)) && print1( i","))

A138928 Indices n such that A020501(n) = phi(n)(-2) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 24, 26, 30, 31, 32, 34, 38, 39, 40, 43, 45, 49, 54, 56, 61, 62, 63, 66, 75, 79, 80, 85, 87, 98, 101, 117, 120, 122, 127, 130, 138, 154, 161, 167, 170, 178, 183, 184, 186, 187, 191, 192, 199, 205, 207, 208
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Comments

While the sequence is not very interesting up to a(n)<300, there are only 4 values in the interval [400,599].

Crossrefs

Programs

  • Mathematica
    Select[ Range[3, 1000], PrimeQ[ Cyclotomic[#, -2]] &] (* Robert G. Wilson v, Mar 25 2012 *)
  • PARI
    for( i=1,999, isprime( polcyclo(i,-2)) && print1( i",")) /* for PARI < 2.4.2 use ...subst(polcyclo(i),x,-2)...*/

A138938 Indices k such that A019326(k)=Phi[k](8) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

1, 3, 9, 30, 42, 78, 87, 138, 189, 303, 318, 330, 408, 462, 504, 561, 1002, 1389, 1746, 1794, 2040, 2418, 2790, 3894, 4077, 4722, 6738, 10641, 14610, 14616, 15294, 16662, 18966, 19059, 26142, 27144, 28299, 31638, 33639, 39360
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[1000], PrimeQ[Cyclotomic[#, 8]] &]
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,8)) && print1( i",")) /* use ...subst( polcyclo(i),x,8)... in PARI < 2.4.2 */

Extensions

a(17)-a(40) from Robert Price, Apr 20 2012

A138922 Indices k such that A020507(k)=Phi[k](-8) is prime, where Phi is a cyclotomic polynomial.

Original entry on oeis.org

6, 15, 18, 21, 39, 69, 159, 165, 174, 231, 378, 408, 501, 504, 606, 873, 897, 1122, 1209, 1395, 1947, 2040, 2361, 2778, 3369, 7305, 7647, 8154, 8331, 9483, 13071, 14616, 15819, 20301, 21282, 27144, 31083, 34725, 35775, 36855, 38118, 39360
Offset: 1

Views

Author

M. F. Hasler, Apr 03 2008

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Range[1000], PrimeQ[Cyclotomic[#, -8]] &]
  • PARI
    for( i=1,999, ispseudoprime( polcyclo(i,-8)) && print1( i",")) /* use ...subst(polcyclo(i),x,-8)... in PARI < 2.4.2 */

Extensions

a(18)-a(42) from Robert Price, Mar 25 2012

A291990 Primes of the form Phi(k, -10), where Phi is the cyclotomic polynomial.

Original entry on oeis.org

101, 9091, 909091, 9901, 909090909090909091, 99990001, 909090909090909090909090909091, 999999000001, 1111111111111111111, 11111111111111111111111, 9999999900000001, 9090909090909090909090909090909090909090909090909091
Offset: 1

Views

Author

Robert Price, Sep 07 2017

Keywords

Crossrefs

Cf. A138920.

Programs

  • Mathematica
    Select[Table[Cyclotomic[k,-10], {k, 3, 100}], PrimeQ[#] &]
Previous Showing 11-19 of 19 results.