A050723 - OEIS

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A050723

Numbers k such that the decimal expansion of 2^k contains no pair of consecutive equal digits (probably finite).

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 20, 21, 22, 28, 29, 30, 31, 32, 34, 35, 36, 37, 48, 54, 55, 56, 66, 67, 68, 69, 80, 87, 104, 126

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

OFFSET

1,3

COMMENTS

No further terms up to 100000. - T. D. Noe, Sep 18 2012

LINKS

Table of n, a(n) for n=1..41.

EXAMPLE

2^126 = 85070591730234615865843651857942052864.

MAPLE

q:= n-> (s-> andmap(i-> s[i]<>s[i+1], [$1..length(s)-1]))(""||(2^n)):

select(q, [$0..200])[]; # Alois P. Heinz, Mar 07 2024