

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
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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(n1) + a(n4)  7*a(n5).
G.f. x*(1+2*x+3*x^2) / ( (x1)*(7*x1)*(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



