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a(0) = 1, a(1) = 2, a(n) = 0 for n > 1.
13

%I #20 Dec 31 2023 10:16:53

%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. Adams-Watters_, Mar 08 2019

%C 2^n mod 4. - _Charles R Greathouse IV_, Apr 30 2019

%F G.f.: 1 + 2*x.

%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 Deléham_, Jun 27 2007