OFFSET
1,1
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..1000
EXAMPLE
4 is a term since 2^4 = 16 has 1 odd digit and 1 even digit.
12 is not a term since 4096 has 1 odd digit and 3 even digits.
13 is a term since 8192 has 2 odd digits and 2 even digits.
MATHEMATICA
ok[n_] := Block[{d=IntegerDigits[2^n]}, EvenQ@ Length@ d && 0 == Plus @@ ((-1)^d) ]; Select[ Range@ 10000, ok] (* Giovanni Resta, May 09 2016 *)
PROG
(PARI) is(n)=my(d=digits(2^n)); #d%2==0 && sum(i=1, #d, (-1)^d[i])==0 \\ Charles R Greathouse IV, May 09 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Seiichi Manyama, May 09 2016
STATUS
approved