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.

A365935 Final digit (in decimal system) of n^(n+1) = A007778(n).

Original entry on oeis.org

0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6
Offset: 0

Views

Author

Marco Ripà, Sep 23 2023

Keywords

Comments

This is a periodic sequence (1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0) with period 20 (which is twice the base).

Examples

			For n = 3, a(3) = 3^4 mod 10 = 81 mod 10 = 1.
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Last[IntegerDigits[n^(n+1)]]; Array[a,87,0] (* Stefano Spezia, Sep 26 2023 *)
  • PARI
    a(n) = lift(Mod(n, 10)^(n+1)); \\ Michel Marcus, Sep 23 2023

Formula

a(n) = n^(n+1) mod 10.
a(n) = A010879(A007778(n)).
a(n) = A365936(n+10).

A365936 Final digit (in decimal system) of n^(n-1) = A000169(n).

Original entry on oeis.org

1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9, 2, 1, 0, 1, 8, 1, 4, 5, 6, 1, 8, 1, 0, 1, 2, 9, 4, 5, 6, 9
Offset: 1

Views

Author

Marco Ripà, Sep 23 2023

Keywords

Comments

This is a periodic sequence with period 20 which is twice the considered radix.

Examples

			For n = 4, a(4) = 4^3 mod 10 = 64 mod 10 = 4.
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Last[IntegerDigits[n^(n-1)]]; Array[a,87] (* Stefano Spezia, Sep 26 2023 *)

Formula

a(n) = n^(n-1) mod 10.
a(n) = A365935(n+10).
Showing 1-2 of 2 results.