A205088 - OEIS

A205088

a(n) = n 8's sandwiched between two 1's.

11, 181, 1881, 18881, 188881, 1888881, 18888881, 188888881, 1888888881, 18888888881, 188888888881, 1888888888881, 18888888888881, 188888888888881, 1888888888888881, 18888888888888881, 188888888888888881, 1888888888888888881, 18888888888888888881

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (11,-10).

FORMULA

a(0) = 11, a(n) = 10*a(n-1) + 71.

a(n) = 1/9*(17*10^(n+1)-71). - Alexander R. Povolotsky, Jan 25 2012

MATHEMATICA

a[0]=11; a[n_] := a[n-1]*10+71; Table[a[n], {n, 0, 44}]

Table[FromDigits[Join[{1}, PadRight[{}, n, 8], {1}]], {n, 0, 20}] (* Harvey P. Dale, Apr 15 2012 *)

PROG

(PARI) a(n)=(170*10^n-71)/9 \\ Charles R Greathouse IV, Jan 23 2012

CROSSREFS

Sequence in context: A106907 A020456 A036935 * A241193 A143413 A009118

Adjacent sequences: A205085 A205086 A205087 * A205089 A205090 A205091

KEYWORD

nonn,easy,less,base

AUTHOR

José María Grau Ribas, Jan 22 2012

STATUS

approved