OFFSET
0,2
COMMENTS
Also seems to be numbers k such that the digits of k^3 are cubes. - Colin Barker, Apr 21 2017
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,10).
FORMULA
From Chai Wah Wu, Sep 03 2020: (Start)
a(n) = 10*a(n-2) for n > 1.
G.f.: (-2*x - 1)/(10*x^2 - 1). (End)
a(n) = (3-(-1)^n)/2 * 10^floor(n/2). - Bernard Schott, Sep 17 2020
MATHEMATICA
Table[FromDigits[IntegerDigits[2^n, 4]], {n, 0, 40}] (* Vincenzo Librandi, Jun 07 2013 *)
Table[{1, 2}10^n, {n, 0, 20}]//Flatten (* Harvey P. Dale, Feb 14 2018 *)
PROG
(PARI) for(n=0, 30, print1(fromdigits(digits(2^n, 4)), ", ")) \\ G. C. Greubel, Sep 10 2018
(Magma) [Seqint(Intseq(2^n, 4)): n in [0..30]]; // G. C. Greubel, Sep 10 2018
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
STATUS
approved