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

Offset: 0

Author

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

Keywords

• nonn
• base
• easy

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.

Crossrefs

Cf. A000079.

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

Programs

Mathematica

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

Scala

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