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A000004 preceded by 1, 2, 4.
6

%I #10 Feb 13 2023 07:47:27

%S 1,2,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

%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 A000004 preceded by 1, 2, 4.

%C Inverse binomial transform of A058331.

%F a(0) = 1, a(1) = 2, a(2) = 4, a(n) = 0 for n > 2.

%F G.f.: (1+2*x+4*x^2).

%o (PARI) {concat([1,2,4],vector(102))}

%Y Cf. A000004 (zero sequence), A058331 (2*n^2+1), A130706 (1, 2, 0, 0, 0, 0, ...), A130779 (1, 1, 2, 0, 0, 0, 0, ...).

%K easy,nonn

%O 0,2

%A _Klaus Brockhaus_, Oct 23 2009