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 A037698 Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,3,0. 2

%I

%S 1,9,66,462,3235,22647,158532,1109724,7768069,54376485,380635398,

%T 2664447786,18651134503,130557941523,913905590664,6397339134648,

%U 44781373942537,313469617597761,2194287323184330

%N Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,3,0.

%H Vincenzo Librandi, <a href="/A037698/b037698.txt">Table of n, a(n) for n = 1..200</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (7,0,0,1,-7).

%F a(n) = 7*a(n-1) + a(n-4) - 7*a(n-5).

%F G.f. x*(1+2*x+3*x^2) / ( (x-1)*(7*x-1)*(1+x)*(x^2+1) ). - R. J. Mathar, Dec 19 2011

%F a(n) = (11*7^(n+1)+(7-(-1)^n)*(25+8*i^(n(n+1)))-275)/400 where i=sqrt(-1). - Bruno Berselli, Dec 19 2011

%t With[{c=PadLeft[{},24,{1,2,3,0}]},Table[FromDigits[Take[c,n],7], {n,20}]] (* or *) LinearRecurrence[{7,0,0,1,-7},{1,9,66,462,3235},20] (* _Harvey P. Dale_, Oct 02 2011 *)

%o (Maxima) makelist((11*7^(n+1)+(7-(-1)^n)*(25+8*%i^(n*(n+1)))-275)/400, n, 1, 19); [Bruno Berselli, Dec 19 2011

%K nonn,base,easy

%O 1,2

%A _Clark Kimberling_

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Last modified June 18 08:40 EDT 2021. Contains 345098 sequences. (Running on oeis4.)