

A263307


Numbers without consecutive repeated digits in base 2 and in base 3.


0




OFFSET

1,2


COMMENTS

Intersection of A000975 and A031941.  Michel Marcus, Oct 14 2015
It seems likely that there are no further terms.


LINKS

Table of n, a(n) for n=1..7.


EXAMPLE

10 is 1010 in base 2 and 101 in base 3; no two of the same digit are next to one another and so 10 is a term.
Similarly 21 is 10101 in base 2 and 210 in base 3 so it is also a term.


PROG

(PARI) isokd(d) = {dd = vector(#d1, k, abs(d[k+1]d[k])); if (#dd, vecmin(dd), 1); }
isok(n) = isokd(binary(n)) && isokd(digits(n, 3)); \\ Michel Marcus, Oct 14 2015


CROSSREFS

Cf. A000975 (base 2), A031941 (base 3).
Sequence in context: A327764 A192317 A151497 * A278441 A323939 A110744
Adjacent sequences: A263304 A263305 A263306 * A263308 A263309 A263310


KEYWORD

nonn,base


AUTHOR

Robin Powell, Oct 13 2015


STATUS

approved



