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 1-6 of 6 results.

A117131 Remainder when n^n is divided by the n-th prime number.

Original entry on oeis.org

1, 1, 2, 4, 1, 12, 12, 7, 2, 6, 24, 26, 11, 6, 30, 15, 9, 41, 39, 32, 51, 64, 78, 4, 72, 43, 89, 25, 31, 109, 26, 62, 80, 36, 9, 72, 132, 140, 105, 52, 132, 135, 117, 147, 79, 193, 93, 49, 175, 76, 64, 187, 196, 9, 163, 221, 190, 62, 102, 280, 71, 87, 102, 268
Offset: 1

Views

Author

Axel Harvey, Jul 23 2006

Keywords

Examples

			a(8)=7 because 8^8 is 16777216, the 8th prime is 19 and 16777216 modulo 19 is 7.
		

Crossrefs

Programs

  • Magma
    [Modexp(n, n, NthPrime(n)): n in [1..100]]; // Vincenzo Librandi, Mar 20 2019
    
  • Maple
    a:= n-> n&^n mod ithprime(n):
    seq(a(n), n=1..81);  # Alois P. Heinz, Mar 20 2019
  • Mathematica
    Table[PowerMod[n, n, Prime[n]], {n, 100}] (* T. D. Noe, Aug 20 2013 *)
  • PARI
    a(n) = lift(Mod(n, prime(n))^n); \\ Michel Marcus, Mar 20 2019

Formula

a(n) = mod(n^n, prime(n)).

Extensions

More terms from Franklin T. Adams-Watters, Jul 26 2006

A167622 a(n) = n^3 mod n-th prime.

Original entry on oeis.org

1, 2, 2, 1, 4, 8, 3, 18, 16, 14, 29, 26, 24, 35, 38, 15, 16, 37, 25, 48, 63, 62, 49, 29, 8, 2, 10, 17, 82, 106, 73, 18, 43, 106, 112, 148, 99, 104, 34, 163, 6, 59, 51, 71, 111, 25, 11, 207, 63, 195, 74, 76, 180, 87, 96, 195, 121, 263, 122, 192, 15, 119, 149, 282, 124, 294
Offset: 1

Views

Author

Zak Seidov, Nov 07 2009

Keywords

Crossrefs

Programs

  • Mathematica
    (*1*) Table[PowerMod[n,3,Prime[n]],{n,100}]
    (*2*) PowerMod[ #,3,Prime[ # ]]&/@Range[100]
  • PARI
    a(n) = lift(Mod(n, prime(n))^3); \\ Michel Marcus, Jan 28 2025
  • Python
    from sympy import sieve
    def A167622(n): return pow(n,3,sieve[n]) # Karl-Heinz Hofmann, Jan 28 2025
    

A167623 a(n) = n^3 mod (n-th prime squared).

Original entry on oeis.org

1, 8, 2, 15, 4, 47, 54, 151, 200, 159, 370, 359, 516, 895, 1166, 1287, 1432, 2111, 2370, 2959, 3932, 4407, 5278, 5903, 6216, 7375, 9074, 10503, 627, 1462, 13662, 15607, 17168, 662, 20674, 1054, 1355, 1734, 3541, 4142, 4839, 8566, 6545, 10686, 13507
Offset: 1

Views

Author

Zak Seidov, Nov 07 2009

Keywords

Crossrefs

Programs

  • Mathematica
    (*1*) Table[PowerMod[n,3,Prime[n]^2],{n,100}]
    (*2*) PowerMod[ #,3,Prime[ # ]^2]&/@Range[100]
  • PARI
    a(n) = lift(Mod(n, prime(n)^2)^3); \\ Michel Marcus, Jan 28 2025
  • Python
    from sympy import sieve
    def A167623(n): return pow(n, 3, sieve[n]**2) # Karl-Heinz Hofmann, Jan 28 2025
    

A096459 Triangle read by rows: T(n,k) = n^2 mod prime(k), 1<=k<=n.

Original entry on oeis.org

1, 0, 1, 1, 0, 4, 0, 1, 1, 2, 1, 1, 0, 4, 3, 0, 0, 1, 1, 3, 10, 1, 1, 4, 0, 5, 10, 15, 0, 1, 4, 1, 9, 12, 13, 7, 1, 0, 1, 4, 4, 3, 13, 5, 12, 0, 1, 0, 2, 1, 9, 15, 5, 8, 13, 1, 1, 1, 2, 0, 4, 2, 7, 6, 5, 28, 0, 0, 4, 4, 1, 1, 8, 11, 6, 28, 20, 33, 1, 1, 4, 1, 4, 0, 16, 17, 8, 24, 14, 21, 5, 0, 1, 1, 0
Offset: 1

Views

Author

Reinhard Zumkeller, Aug 12 2004

Keywords

Comments

T(n,k)=0 iff k is a prime factor of n:
A001221(n) = number of zeros in n-th row;
T(n,1)=A000035(n);
T(n,2)=A011655(n) for n>1; T(n,3)=A070430(n) for n>2;
T(n,4)=A053879(n) for n>3; T(n,5)=A070434(n) for n>4;
T(n,6)=A070436(n) for n>5; T(n,7)=A054580(n) for n>6;
T(n,8)=A070441(n) for n>7; T(n,9)=A070445(n) for n>8;
T(n,10)=A070451(n) for n>9;
T(n,n)=A069547(n).

Examples

			Triangle begins:
1;
0, 1;
1, 0, 4;
0, 1, 1, 2;
1, 1, 0, 4, 3;
0, 0, 1, 1, 3, 10;
1, 1, 4, 0, 5, 10, 15;
......
		

Crossrefs

Programs

  • Mathematica
    Table[Mod[n^2, Prime[k]], {n, 1, 10}, {k, 1, n}] (* G. C. Greubel, May 20 2017 *)

A097882 a(n) = floor( n^2/prime(n) ).

Original entry on oeis.org

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

Views

Author

Reinhard Zumkeller, Sep 02 2004

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Floor[n^2/Prime[n]], {n,1,50}] (* G. C. Greubel, May 21 2017 *)
  • PARI
    for(n=1,50, print1(floor(n^2/prime(n)), ", ")) \\ G. C. Greubel, May 21 2017

Formula

a(n) = floor(A000290(n)/A000040(n)).
A000290(n) = a(n)*A000040(n) + A069547(n).

A152526 Numbers k with property that (k^2 mod prime(k)) < 10.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 13, 21, 27, 44, 104, 365, 5477, 16787, 20272, 446691, 1793239, 9806042, 198017575, 2830612574
Offset: 1

Views

Author

Zak Seidov, Oct 27 2009

Keywords

Comments

Numbers k with property that A069547(k) < 10.
a(21) > 4.4*10^10, if it exists. - Amiram Eldar, Jul 04 2021

Examples

			(n, A069547(n)): (1,1),(2,1),(3,4),(4,2),(5,3),(8,7),(13,5),(21,3),(27,8),(44,6),(104,5),(365,7),(5477,7),(16787,8),(20272,3),(446691,5),(1793239,8),(9806042,2),(198017575,2),(2830612574, 6).
198017575^2 = 9384391*prime(198017575) + 2.
		

Crossrefs

Cf. A069547 (n^2 mod n-th prime).

Programs

  • Mathematica
    Do[m=PowerMod[n,2,Prime[n]];If[m<10,Print[{n,m}]],{n,2*10^8}]

Extensions

a(20) from Amiram Eldar, Jul 04 2021
Showing 1-6 of 6 results.