

A320930


Numbers n such that 4^n starts with n.


0




OFFSET

1,1


LINKS

Table of n, a(n) for n=1..10.


EXAMPLE

4^10 = 1048576 starts with 10, so 10 is in the sequence.


MAPLE

filter:= proc(n) local t, b;
t:= 4^n;
b:= ilog10(t)  ilog10(n);
floor(t/10^b) = n
end proc:
select(filter, [$1..10^5]);


CROSSREFS

Cf. A100129, A288845.
Sequence in context: A177185 A241281 A002744 * A337325 A156382 A214894
Adjacent sequences: A320927 A320928 A320929 * A320931 A320932 A320933


KEYWORD

nonn,base,more


AUTHOR

Robert Israel, Oct 24 2018


EXTENSIONS

a(8)a(10) from Giovanni Resta, Oct 25 2018


STATUS

approved



