

A131542


Least power of 2 having exactly n consecutive 8's in its decimal representation.


2



3, 19, 39, 180, 316, 971, 6836, 25263, 103825, 279274, 279268, 1727604, 18053496, 8760852
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

No more terms < 28*10^6.


LINKS

Popular Computing (Calabasas, CA), Two Tables, Vol. 1, (No. 9, Dec 1973), page PC916.


EXAMPLE

a(3)=39 because 2^39(i.e. 549755813888) is the smallest power of 2 to contain a run of 3 consecutive eights in its decimal form.


MATHEMATICA

a = ""; Do[ a = StringJoin[a, "8"]; b = StringJoin[a, "8"]; k = 1; While[ StringPosition[ ToString[2^k], a] == {}  StringPosition[ ToString[2^k], b] != {}, k++ ]; Print[k], {n, 1, 10} ]


CROSSREFS



KEYWORD

more,nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



