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 1-2 of 2 results.

A218766 Composite numbers with both 10 and -10 as primitive root.

Original entry on oeis.org

289, 841, 3721, 4913, 9409, 11881, 12769, 22201, 24389, 32761, 37249, 52441, 54289, 66049, 72361, 83521, 97969, 113569, 151321, 187489, 212521, 226981, 259081, 292681, 332929, 351649, 491401, 502681, 674041, 707281, 734449, 877969, 885481, 908209, 912673
Offset: 1

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Author

Arkadiusz Wesolowski, Nov 05 2012

Keywords

Comments

The powers of primes from A007349.
Intersection of A002808, A167797 and A167806.

Examples

			12769 = 113^2 belongs to this sequence because 113 is in A007349.
		

Crossrefs

Cf. A007349.

Programs

  • Mathematica
    lst = {}; r = 912673; Do[If[PrimeQ[i] && MultiplicativeOrder[10, i] == MultiplicativeOrder[-10, i] == i - 1, n = 2; While[(p = i^n) <= r, AppendTo[lst, p]; n++]], {i, Floor@Sqrt[r]}]; Sort[lst]

A381590 Primes with primitive root -100.

Original entry on oeis.org

3, 7, 19, 23, 31, 43, 47, 59, 67, 71, 83, 107, 131, 151, 163, 167, 179, 191, 199, 223, 227, 263, 283, 307, 311, 347, 359, 367, 379, 383, 419, 431, 439, 443, 467, 479, 487, 491, 499, 503, 523, 563, 571, 587, 599, 619, 631, 647, 659, 683, 719, 727, 743, 787, 811
Offset: 1

Views

Author

Davide Rotondo, Feb 28 2025

Keywords

Comments

Union of long period primes (A006883) of the form 4k-1 and half period primes (A097443) of the form 4k-1.
Complement of A007349 in the union of A007348 and A001913. - Davide Rotondo, May 23 2025

Crossrefs

Programs

  • Mathematica
    Select[Prime[Range[150]], MultiplicativeOrder[-100, #] == # - 1 &]  (* Amiram Eldar, Mar 02 2025 *)
  • PARI
    is(n)=gcd(n,10)==1 && znorder(Mod(-100, n))==n-1 \\ Charles R Greathouse IV, Mar 01 2025
    
  • PARI
    list(lim)=my(v=List([3])); forprime(p=7,lim, if(znorder(Mod(-100, p))==p-1, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Mar 01 2025
Showing 1-2 of 2 results.