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A000455

Digits of powers of 2.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

The number 0.a(0)a(1)a(2)...=0.124816... is a rich (or disjunctive) number. - Robert FERREOL, Apr 01 2020

The constant whose decimal expansion is this sequence is irrational (Mahler, 1981). - Amiram Eldar, Mar 23 2025

REFERENCES

David Gale, Tracking the Automatic ANT And Other Mathematical Explorations, 1998, pp. 42-43.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 0..9999

Archimedeans, The Problems Drive, Eureka, Vol. 11 (1949), p. 10, problem (5) B.

Kurt Mahler, On some irrational decimal fractions, Journal of Number Theory, Vol. 13, No. 2 (1981), pp. 268-269.

MATHEMATICA

2^Range[0, 25] // IntegerDigits // Flatten (* Jean-François Alcover, Feb 08 2016 *)

PROG

(Scala) (List.fill(32)(2: BigInt)).scanLeft(1: BigInt)(_ * _).map(_.toString.toCharArray).flatten.map(_.toInt - 48) // Alonso del Arte, Mar 28 2020

CROSSREFS

Cf. A000079.

Cf. A008564, A008565, A008566, A008567, A008568, A008569, A008570, A008571, A008572, A008573, A010054.

Sequence in context: A210026 A100880 A102256 * A282821 A317495 A317504

Adjacent sequences: A000452 A000453 A000454 * A000456 A000457 A000458

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane; entry revised by N. J. A. Sloane, Jun 10 2012

STATUS

approved

URL: https://oeis.org/A000455

⇱ A000455 - OEIS