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 1-3 of 3 results.

A256148 Primitive prime factors of the cyclotomic polynomial sequence Phi(3, k) (or Phi(6, k)) in the order in which they occur.

Original entry on oeis.org

3, 7, 13, 31, 43, 19, 73, 37, 157, 61, 211, 241, 307, 127, 421, 463, 79, 601, 757, 271, 67, 331, 151, 1123, 397, 97, 1483, 223, 547, 1723, 139, 631, 283, 109, 103, 181, 2551, 379, 919, 409, 2971, 3307, 163, 3541, 523, 3907, 613, 4423, 4831, 1657, 5113, 751
Offset: 1

Views

Author

Robert Price, Mar 16 2015

Keywords

Comments

Phi(3,k) = k^2 + k + 1 and Phi(6,k) = k^2 - k + 1.
Interesting scatter plot.
The terms correspond to the new primes of A081257 in the order of their appearance for n>1 and when A081257(m)>m. - Bill McEachen, Oct 13 2022

Links

Crossrefs

Cf. A005529, A248874, A256144, A256145, A256146, A081257.

Programs

  • Mathematica
    prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[6, k]], prim]], {k, 1000}]; prim
  • PARI
    lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(6,n))[,1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]),,8););););} \\ Michel Marcus, Mar 20 2015

A256146 Primitive prime factors of the cyclotomic polynomial sequence Phi(7,k) in the order in which they occur.

Original entry on oeis.org

7, 127, 1093, 43, 19531, 55987, 29, 4733, 337, 547, 239, 4649, 45319, 659, 4943, 5229043, 8108731, 1743463, 113, 25646167, 449, 80207, 701, 70841, 71, 32719, 631, 3319, 16968421, 5336717, 28771, 321272407, 368089, 4422461, 88009573, 93997, 917087137, 122921
Offset: 1

Views

Author

Robert Price, Mar 16 2015

Keywords

Comments

Phi(7,k) = k^6 + k^5 + k^4 + k^3 + k^2 + k + 1.

Links

Crossrefs

Cf. A005529, A248874, A256144, A256145.

Programs

  • Mathematica
    prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[7, k]], prim]], {k, 1000}]; prim
  • PARI
    lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(7,n))[,1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]),,8););););} \\ Michel Marcus, Mar 20 2015

A256153 Primitive prime factors of the cyclotomic polynomial sequence Phi(5,k) in the order in which they occur.

Original entry on oeis.org

5, 31, 11, 71, 311, 2801, 151, 61, 41, 271, 3221, 22621, 30941, 3761, 4931, 88741, 2711, 911, 251, 40841, 245411, 292561, 346201, 521, 8641, 4561, 637421, 732541, 837931, 17351, 601, 1801, 39451, 22571, 49831, 101, 4271, 194681, 191, 401, 2625641, 579281
Offset: 1

Views

Author

Robert Price, Mar 16 2015

Keywords

Comments

Phi(5,k) = k^4 + k^3 + k^2 + k + 1.
All terms end with the digit 1.

Links

Crossrefs

Cf. A005529, A248874, A256144, A256145, A256146, A256148.

Programs

  • Mathematica
    prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[5, k]], prim]], {k, 1000}]; prim
  • PARI
    lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(5,n))[,1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]),,8););););} \\ Michel Marcus, Mar 20 2015
Showing 1-3 of 3 results.

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

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