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%I #19 Apr 09 2024 05:45:52
%S 1,5,35,245,1715,12005,84035,588245,4117715,28824005,201768035,
%T 1412376245,9886633715,69206436005,484445052035,3391115364245,
%U 23737807549715,166164652848005,1163152569936035,8142067989552245,56994475926865715,398961331488060005
%N Expansion of (1-2x)/(1-7x).
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (7).
%F a(0) = 1, a(n) = 5*7^(n-1) for n>0.
%F a(n) = Sum_{k=0..n} A193722(n,k)*2^k.
%o (PARI) a(n)=if(n,5*7^(n-1),1) \\ _Charles R Greathouse IV_, Nov 21 2011
%Y Cf. A002001, A193722, A193577 (which is the same except for the initial 1).
%K nonn,easy
%O 0,2
%A _Philippe Deléham_, Oct 05 2011