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%I #16 Sep 08 2022 08:46:14
%S 41,68921,115856201,194754273881,327381934393961,550329031716248441,
%T 925103102315013629321,1555098314991537910888601,
%U 2614120267500775228203738281,4394336169668803158610484050361,7386879101213258109624223688656841,12417343769139486882278320020632149721
%N a(n) = 41^(2*n+1).
%C 41*a(n) is a square.
%H G. C. Greubel, <a href="/A262787/b262787.txt">Table of n, a(n) for n = 0..250</a>
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1681).
%F G.f.: 41/(1 - 1681*x).
%F a(n) = 1681*a(n-1).
%p A262787:=n->41^(2*n+1): seq(A262787(n), n=0..20); # _Wesley Ivan Hurt_, Dec 26 2016
%t 41^Range[1, 30, 2]
%o (Magma) [41^(2*n+1): n in [0..15]];
%o (PARI) vector(20, n, n--; 41^(2*n+1)) \\ _Altug Alkan_, Oct 08 2015
%Y Second bisection of A009985 (powers of 41).
%Y Cf. similar sequences listed in A262715.
%K nonn,easy
%O 0,1
%A _Vincenzo Librandi_, Oct 08 2015
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