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

1, 9, 66, 462, 3235, 22647, 158532, 1109724, 7768069, 54376485, 380635398, 2664447786, 18651134503, 130557941523, 913905590664, 6397339134648, 44781373942537, 313469617597761, 2194287323184330

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (7,0,0,1,-7).

Formula

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

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

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

Mathematica

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 *)

Prog

(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 */

Crossrefs

Sequence in context: A081902 A002695 A003408 * A037607 A055148 A014830

Adjacent sequences: A037695 A037696 A037697 * A037699 A037700 A037701

Keyword

nonn,base,easy

Author

Clark Kimberling

Status

approved