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.

A364789 Initial digit of (n^n)^n (A002489(n)).

Original entry on oeis.org

1, 1, 1, 1, 4, 2, 1, 2, 6, 1, 1, 1, 2, 1, 4, 4, 1, 3, 5, 4, 2, 1, 5, 2, 1, 5, 3, 2, 3, 7, 2, 1, 1, 4, 2, 3, 9, 7, 1, 1, 1, 1, 2, 1, 5, 5, 2, 4, 3, 1, 2, 2, 1, 3, 4, 3, 2, 6, 1, 2, 2, 1, 8, 3, 1, 3, 8, 1, 3, 5, 9, 1, 2, 4, 8, 1, 3, 1, 3, 1, 5, 3, 3, 3, 5, 1, 3
Offset: 0

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Author

Marco Ripà, Aug 08 2023

Keywords

Comments

a(0) = 1 is from (0^0)^0 = 1 per A002489.
The author conjectures that this sequence obeys the well-known Benford's law.

Examples

			a(4) = 4, since (4^4)^4 = 4^(4^2) = 4294967296.
		

Crossrefs

Cf. A229522 (final digit).

Programs

Formula

a(n) = floor(((n^n)^n)/10^floor(log_10((n^n)^n))).
a(n) = A000030(A002489(n)).

A364855 Initial digit of 3^(3^n) (A055777(n)).

Original entry on oeis.org

3, 2, 1, 7, 4, 8, 6, 2, 2, 1, 3, 3, 6, 2, 1, 3, 3, 4, 6, 2, 2, 1, 1, 1, 5, 1, 2, 1, 1, 7, 4, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 7, 4, 8, 6, 2, 1, 2, 1, 3, 4, 1, 1, 1, 4, 8, 6, 2, 2, 1, 2, 2, 1, 5, 1, 6, 3, 3, 4, 1, 1, 2, 1, 5, 1, 4, 1
Offset: 0

Views

Author

Marco Ripà, Aug 10 2023

Keywords

Comments

This sequence corresponds to the initial digit of 3vvn (since 3^(3^n) = ((((3^3)^3)^...)^3) n-times), where vv indicates weak tetration (see links).
The author conjectures that the distribution of the initial digits of the present sequence obey Benford's law or Zipf's law (see links).
The corresponding final digit of 3^(3^n) is A010705(n) = 3 if n even or 7 if n odd.

Examples

			a(2) = 1, since 3^(3^2) = 3^9 = 19683.
		

References

  • A. Iorliam, Natural Laws (Benford's Law and Zipf's Law) For Network Traffic Analysis, In: Cybersecurity in Nigeria. SpringerBriefs in Cybersecurity. Springer, Cham (2019), 3-22. DOI: 10.1007/978-3-030-15210-9_2

Crossrefs

Cf. A000030, A010705 (last digit), A055777, A364789, A364837.

Programs

  • Mathematica
    Join[{3},Table[Floor[3^(3^n)/10^Floor[Log10[3^(3^n)]]],{n,16}]]

Formula

a(n) = floor(3^(3^n)/10^floor(log_10(3^(3^n)))).
a(n) = A000030(A055777(n)).

Extensions

More terms from Jinyuan Wang, Aug 11 2023
Showing 1-2 of 2 results.