A013786 - OEIS

%I #25 Oct 04 2024 19:08:44

%S 7,16807,40353607,96889010407,232630513987207,558545864083284007,

%T 1341068619663964900807,3219905755813179726837607,

%U 7730993719707444524137094407,18562115921017574302453163671207,44567640326363195900190045974568007

%N a(n) = 7^(4*n + 1).

%H Vincenzo Librandi, <a href="/A013786/b013786.txt">Table of n, a(n) for n = 0..200</a>

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (2401).

%F From _Philippe Deléham_, Dec 02 2008: (Start)

%F a(n) = 2401*a(n-1); a(0)=7.

%F G.f.: 7/(1-2401*x).

%F a(n) = A013787(n)/49. (End)

%t NestList[2401#&,7,20] (* _Harvey P. Dale_, Oct 04 2024 *)

%o (Magma) [7^(4*n+1): n in [0..15]]; // _Vincenzo Librandi_, Jun 28 2011

%o (PARI) a(n)=7^(4*n+1) \\ _Charles R Greathouse IV_, Jul 11 2016

%Y Subsequence of A000420.

%K nonn,easy

%O 0,1

%A _N. J. A. Sloane_