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a(n) = [x^n] (Sum_{j>=0} A002193(1-j) * x^j)^2.
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%I #17 Jun 02 2020 12:53:09

%S 1,8,18,16,37,26,34,52,70,90,87,116,127,112,157,212,158,192,252,252,

%T 249,272,349,276,287,478,482,334,407,478,465,488,544,698,562,504,682,

%U 698,738,736,742,880,907,826,944,848,998,1110,976,1106,1217,1112,1060

%N a(n) = [x^n] (Sum_{j>=0} A002193(1-j) * x^j)^2.

%F G.f.: (Sum_{j>=0} A002193(1-j) * x^j)^2.

%F Sum_{k>=0} a(k)/10^k = 2.

%F a(n) = Sum_{j=0..n} A002193(1-j)*A002193(j-n+1).

%e a(1) = 8 because the coefficient of x^1 in (1 + 4x + ... )^2 is 8.

%o (PARI) seq(n)={Vec(Ser(digits(sqrtint(2*100^n)))^2)} \\ _Andrew Howroyd_, Mar 04 2020

%Y Cf. A002193.

%K nonn,base,easy

%O 0,2

%A _Andrew Slattery_, Mar 04 2020