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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
1, 9, 66, 462, 3235, 22647, 158532, 1109724, 7768069, 54376485, 380635398, 2664447786, 18651134503, 130557941523, 913905590664, 6397339134648, 44781373942537, 313469617597761, 2194287323184330 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 9 20:41 EDT 2021. Contains 343746 sequences. (Running on oeis4.)