%I
%S 1,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%T 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
%U 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
%N a(0) = 1, a(1) = 2, a(n) = 0 for n > 1.
%C Inverse binomial transform of A005408.
%C Decimal expansion of 3/25.  _Franklin T. AdamsWatters_, Mar 08 2019
%C 2^n mod 4.  _Charles R Greathouse IV_, Apr 30 2019
%F G.f.: 1 + 2*x.
%F a(n) = [C(2*n, n) mod 2] + 2*[C((n + 1)^2, n + 3) mod 2], n >= 0.  _Paolo P. Lava_, Oct 22 2007
%t RealDigits[12, 10, 100][[1]] (* _Alonso del Arte_, Sep 16 2016 *)
%o (PARI) .12 \\ _Charles R Greathouse IV_, Sep 16 2016
%K easy,nonn
%O 0,2
%A _Philippe DelĂ©ham_, Jun 27 2007
