

A050725


Decimal expansion of 4^n contains no pair of consecutive equal digits (probably finite).


1



0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 14, 15, 16, 17, 18, 24, 27, 28, 33, 34, 40, 52, 63
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,3


COMMENTS



LINKS



EXAMPLE

4^63 = 85070591730234615865843651857942052864.


MATHEMATICA

Select[Range[0, 70], FreeQ[Differences[IntegerDigits[4^#]], 0]&] (* Harvey P. Dale, Jul 25 2013 *)


PROG

(PARI) isok(n) = {my(d = digits(4^n), c = d[1]); for (i=2, #d, if (d[i] == c, return (0)); c = d[i]; ); return (1); } \\ Michel Marcus, Oct 16 2019


CROSSREFS



KEYWORD

nonn,base,more


AUTHOR



STATUS

approved



