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%I #16 Sep 08 2022 08:45:03
%S 1,40,1200,32000,800000,19200000,448000000,10240000000,230400000000,
%T 5120000000000,112640000000000,2457600000000000,53248000000000000,
%U 1146880000000000000,24576000000000000000,524288000000000000000,11141120000000000000000,235929600000000000000000
%N a(n) = n*20^(n-1).
%H Harry J. Smith, <a href="/A061650/b061650.txt">Table of n, a(n) for n = 1..100</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (40,-400).
%F G.f.: x /(1 - 20*x)^2. - _Vincenzo Librandi_, Jul 02 2018
%F a(n) = n*20^(n-1).
%t CoefficientList[Series[(1)/(1 - 20 x)^2, {x, 0, 20}], x] (* _Vincenzo Librandi_, Jul 02 2018 *)
%t LinearRecurrence[{40,-400},{1,40},20] (* _Harvey P. Dale_, Aug 01 2021 *)
%o (PARI) { for (n=1, 100, write("b061650.txt", n, " ", n*20^(n - 1)) ) } \\ _Harry J. Smith_, Jul 25 2009
%o (Magma) [n*20^(n-1): n in [1..20]]; // _Vincenzo Librandi_, Jul 02 2018
%K easy,nonn
%O 1,2
%A _Jason Earls_, Jun 14 2001
%E Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jun 18 2001
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