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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A380531 a(n) is the multiplicative order of -4 modulo prime(n); a(1) = 0 for completion.

Original entry on oeis.org

0, 2, 1, 6, 10, 3, 4, 18, 22, 7, 10, 9, 5, 14, 46, 13, 58, 15, 66, 70, 18, 78, 82, 22, 24, 25, 102, 106, 9, 7, 14, 130, 17, 138, 37, 30, 13, 162, 166, 43, 178, 45, 190, 48, 49, 198, 210, 74, 226, 19, 58, 238, 12, 50, 8, 262, 67, 270, 23, 70
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Comments

a(n) divides (p-1)/4 if p = prime(n) == 1 (mod 4), since (-4)^((p-1)/4) == (+-1+-i)^(p-1) == 1 (mod p), where i^2 == -1 (mod p).

Crossrefs

Cf. A105876 (primes having primitive root -4).
Cf. bases -2..-10: A337878 (if first term 1), A380482, this sequence, A380532, A380533, A380540, A380541, A380542, A385222.

Programs

  • Mathematica
    A380531[n_] := If[n == 1, 0, MultiplicativeOrder[-4, Prime[n]]];
    Array[A380531, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-4}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A380532 a(n) is the multiplicative order of -5 modulo prime(n); a(3) = 0 for completion.

Original entry on oeis.org

1, 1, 0, 3, 10, 4, 16, 18, 11, 7, 6, 36, 20, 21, 23, 52, 58, 15, 11, 10, 72, 78, 41, 44, 96, 50, 51, 53, 54, 112, 21, 130, 136, 138, 74, 150, 156, 27, 83, 172, 178, 30, 38, 192, 196, 66, 70, 111, 113, 57, 232, 238, 40, 50, 256, 131, 134, 54, 276, 140
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A105877 (primes having primitive root -5).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, this sequence, A380533, A380540, A380541, A380542, A385222.

Programs

  • Mathematica
    A380532[n_] := If[n == 3, 0, MultiplicativeOrder[-5, Prime[n]]];
    Array[A380532, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-5}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A094593 a(n) = (p-1)/x, where p = prime(n) and x = ord(3,p), the smallest positive integer such that 3^x == 1 mod p.

Original entry on oeis.org

1, 1, 2, 4, 1, 1, 2, 1, 1, 2, 5, 1, 2, 1, 2, 6, 3, 2, 6, 1, 2, 1, 2, 1, 3, 2, 4, 1, 1, 2, 1, 1, 1, 3, 2, 1, 2, 1, 2, 4, 2, 12, 1, 1, 1, 1, 2, 4, 1, 2, 2, 2, 1, 2, 1, 9, 4, 1, 1, 1, 9, 2, 8, 1, 1, 2, 2, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 2, 4, 10, 16, 3, 2, 1, 2
Offset: 3

Views

Author

Benoit Cloitre, Jun 06 2004

Keywords

Crossrefs

Cf. A001917.

Programs

  • PARI
    a(n)=(prime(n)-1)/if(n<0,0,k=1;while((3^k-1)%prime(n)>0,k++);k)
    
  • Python
    from sympy import prime, n_order
    def A094593(n):
        p = prime(n)
        return 1 if n == 3 else (p-1)//n_order(3,p) # Chai Wah Wu, Jan 15 2020

Formula

a(n) = (A000040(n)-1)/A062117(n).

A380533 a(n) is the multiplicative order of -6 modulo prime(n); a(1) = a(2) = 0 for completion.

Original entry on oeis.org

0, 0, 2, 1, 5, 12, 16, 18, 22, 7, 3, 4, 40, 6, 46, 13, 29, 60, 66, 70, 36, 39, 41, 88, 12, 5, 51, 53, 108, 112, 63, 65, 136, 46, 74, 75, 156, 54, 166, 86, 89, 60, 38, 96, 7, 99, 210, 111, 113, 228, 232, 34, 20, 125, 256, 262, 67, 135, 276, 56
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A105878 (primes having primitive root -6).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, this sequence, A380540, A380541, A380542, A385222.

Programs

  • Mathematica
    A380533[n_] := If[n < 3, 0, MultiplicativeOrder[-6, Prime[n]]];
    Array[A380533, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-6}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A380540 a(n) is the multiplicative order of -7 modulo prime(n); a(4) = 0 for completion.

Original entry on oeis.org

1, 2, 4, 0, 5, 12, 16, 6, 11, 14, 30, 18, 40, 3, 46, 13, 58, 60, 33, 35, 24, 39, 82, 88, 96, 100, 102, 53, 54, 7, 63, 130, 68, 138, 37, 75, 52, 81, 166, 172, 89, 12, 5, 24, 49, 198, 105, 74, 226, 228, 116, 119, 240, 250, 256, 131, 268, 270, 69, 20
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A105879 (primes having primitive root -7).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, A380533, this sequence, A380541, A380542, A385222.

Programs

  • Mathematica
    A380540[n_] := If[n == 4, 0, MultiplicativeOrder[-7, Prime[n]]];
    Array[A380540, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-7}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A380541 a(n) is the multiplicative order of -8 modulo prime(n); a(1) = 0 for completion.

Original entry on oeis.org

0, 1, 4, 2, 5, 4, 8, 3, 22, 28, 10, 12, 20, 7, 46, 52, 29, 20, 11, 70, 6, 26, 41, 22, 16, 100, 34, 53, 12, 28, 14, 65, 68, 23, 148, 10, 52, 27, 166, 172, 89, 60, 190, 32, 196, 66, 35, 74, 113, 76, 58, 238, 8, 25, 16, 262, 268, 90, 92, 35
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A105880 (primes having primitive root -8).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, A380533, A380540, this sequence, A380542, A385222.

Programs

  • Mathematica
    A380541[n_] := If[n == 1, 0, MultiplicativeOrder[-8, Prime[n]]];
    Array[A380541, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-8}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

Formula

a(n) = ord(-2,p)/gcd(ord(-2,p),3) for p != 2, where p = prime(n), and ord(a,m) is the multiplicative order of a modulo m. Note that ord(-2,p) = A337878(n) for n > 2.

A380542 a(n) is the multiplicative order of -9 modulo prime(n); a(2) = 0 for completion.

Original entry on oeis.org

1, 0, 1, 6, 10, 6, 8, 18, 22, 7, 30, 18, 4, 42, 46, 13, 58, 10, 22, 70, 3, 78, 82, 44, 24, 25, 34, 106, 54, 56, 126, 130, 68, 138, 37, 50, 78, 162, 166, 43, 178, 90, 190, 8, 49, 198, 210, 222, 226, 114, 116, 238, 60, 250, 128, 262, 67, 30, 138, 140
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A105881 (primes having primitive root -9).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, A380533, A380540, A380541, this sequence, A385222.

Programs

  • Mathematica
    A380542[n_] := If[n == 2, 0, MultiplicativeOrder[-9, Prime[n]]];
    Array[A380542, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-9}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A385222 a(n) is the multiplicative order of -10 modulo prime(n); a(1) = a(3) = 0 for completion.

Original entry on oeis.org

0, 2, 0, 3, 1, 3, 16, 9, 11, 28, 30, 6, 10, 42, 23, 26, 29, 60, 66, 70, 8, 26, 82, 44, 96, 4, 17, 106, 108, 112, 21, 65, 8, 23, 148, 150, 39, 162, 83, 86, 89, 180, 190, 192, 49, 198, 15, 111, 226, 228, 232, 14, 15, 25, 256, 131, 268, 10, 138, 28
Offset: 1

Views

Author

Jianing Song, Jun 27 2025

Keywords

Crossrefs

Cf. A007348 (primes having primitive root -10).
Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, A380533, A380540, A380541, A380542, this sequence.

Programs

  • Mathematica
    A385222[n_] := If[n == 1 || n == 3, 0, MultiplicativeOrder[-10, Prime[n]]];
    Array[A385222, 100] (* Paolo Xausa, Jun 29 2025 *)
  • PARI
    a(n,{k=-10}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))

A385226 Odd multiplicative orders of 3 modulo primes.

Original entry on oeis.org

1, 5, 3, 11, 23, 29, 35, 41, 53, 27, 65, 83, 89, 45, 95, 113, 57, 119, 125, 131, 69, 155, 39, 173, 179, 191, 209, 105, 43, 27, 221, 233, 239, 49, 251, 135, 281, 293, 299, 75, 323, 329, 31, 177, 359, 183, 371, 9, 413, 207, 419, 431, 443, 455, 473, 485, 491
Offset: 1

Views

Author

Jianing Song, Jun 22 2025

Keywords

Comments

a(n) is the multiplicative order of 3 modulo A385220(n).
Odd elements in A062117.

Crossrefs

Cf. A062117, A385220 (corresponding primes).
Cf. other bases: A139686 (base 2), this sequence (base 3), A385227 (base 4), A385193 (base 5), A385228 (base -2), A385229 (base -3), A385230 (base -4), A385231 (base -5).

Programs

  • Mathematica
    Select[Map[MultiplicativeOrder[3, #] &, Prime[Range[200]]], OddQ] (* Paolo Xausa, Jun 28 2025 *)
  • PARI
    forprime(p=2, 1e4, if(p!=3, z=znorder(Mod(3, p)); if(z%2, print1(z, ", "))))

A201909 Irregular triangle of 3^k mod prime(n).

Original entry on oeis.org

1, 0, 1, 3, 4, 2, 1, 3, 2, 6, 4, 5, 1, 3, 9, 5, 4, 1, 3, 9, 1, 3, 9, 10, 13, 5, 15, 11, 16, 14, 8, 7, 4, 12, 2, 6, 1, 3, 9, 8, 5, 15, 7, 2, 6, 18, 16, 10, 11, 14, 4, 12, 17, 13, 1, 3, 9, 4, 12, 13, 16, 2, 6, 18, 8, 1, 3, 9, 27, 23, 11, 4, 12, 7, 21, 5, 15
Offset: 1

Views

Author

T. D. Noe, Dec 07 2011

Keywords

Comments

The row lengths are in A062117. Except for the second row, the first term of each row is 1. Many sequences are in this one: starting at A036119 (mod 17) and A070341 (mod 11).

Examples

			The first 9 rows are:
  1
  0
  1, 3, 4,  2
  1, 3, 2,  6,  4,  5
  1, 3, 9,  5,  4
  1, 3, 9
  1, 3, 9, 10, 13,  5, 15, 11, 16, 14,  8,  7,  4, 12, 2,  6
  1, 3, 9,  8,  5, 15,  7,  2,  6, 18, 16, 10, 11, 14, 4, 12, 17, 13
  1, 3, 9,  4, 12, 13, 16,  2,  6, 18,  8
		

Crossrefs

Cf. A062117, A201908 (2^k), A201910 (5^k), A201911 (7^k).
Cf. A070352 (5), A033940 (7), A070341 (11), A168399 (13), A036119 (17), A070342 (19), A070356 (23), A070344 (29), A036123 (31), A070346 (37), A070361 (41), A036126 (43), A070364 (47), A036134 (79), A036136 (89), A036142 (113), A036143 (127), A036145 (137), A036158 (199), A036160 (223).

Programs

  • GAP
    P:=Filtered([1..350],IsPrime);;
    R:=List([1..Length(P)],n->OrderMod(7,P[n]));;
    Flat(Concatenation([1,1,1,2,4,3,0],List([5..10],n->List([0..R[n]-1],k->PowerMod(7,k,P[n]))))); # Muniru A Asiru, Feb 01 2019
  • Mathematica
    nn = 10; p = 3; t = p^Range[0,Prime[nn]]; Flatten[Table[If[Mod[n, p] == 0, {0}, tm = Mod[t, n]; len = Position[tm, 1, 1, 2][[-1,1]]; Take[tm, len-1]], {n, Prime[Range[nn]]}]]
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