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%I #20 Mar 15 2024 11:55:44
%S 3,1,0,0,0,0,0,1,2,3,4,6,9,10,12,15,18,21,24,28,32,36,40,45,51,55,60,
%T 66,72,78,84,91,98,105,112,120,129,136,144,153,162,171,180,190,200,
%U 210,220,231,243,253,264,276,288,300,312,325,338,351,364,378,393,406,420
%N Exponent sequence for a bilinear recursive sequence.
%H <a href="/index/Tu#2wis">Index entries for two-way infinite sequences</a>
%H <a href="/index/Rec#order_14">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,0,0,0,0,0,0,0,0,0,1,-2,1).
%F G.f.: (3 - 5*x + x^2 + x^3 + x^7 + x^11 - 2*x^12 + 3*x^13) / ((1 - x)^2 * (1 - x^12)).
%F a(8-n) - a(n) = -1 if n == 0 (mod 12), +1 if n == 8 (mod 12), 0 otherwise.
%e 3 + x + x^7 + 2*x^8 + 3*x^9 + 4*x^10 + 6*x^11 + 9*x^12 + 10*x^13 + ...
%t LinearRecurrence[{2,-1,0,0,0,0,0,0,0,0,0,1,-2,1},{3,1,0,0,0,0,0,1,2,3,4,6,9,10},70] (* _Harvey P. Dale_, May 27 2017 *)
%o (PARI) {a(n) = (n%12==0) + (n-4)^2\8}
%Y Cf. A001972, A078530.
%K nonn,easy
%O 0,1
%A _Michael Somos_, Nov 25 2002
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