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A033175 n 3's followed by 1. 10
1, 31, 331, 3331, 33331, 333331, 3333331, 33333331, 333333331, 3333333331, 33333333331, 333333333331, 3333333333331, 33333333333331, 333333333333331, 3333333333333331, 33333333333333331, 333333333333333331 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

F. Smarandache, Properties of numbers, University of Craiova, 1973

LINKS

Table of n, a(n) for n=0..17.

Eric Weisstein's World of Mathematics, 3

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

FORMULA

a(n) = (10^(n+1)-7)/3.

a(n) = 10*a(n-1)+21 (with a(0)=1) [From Vincenzo Librandi, Nov 17 2010]

G.f.: ( 1+20*x ) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Aug 24 2011

MATHEMATICA

Table[FromDigits[PadLeft[{1}, n, 3]], {n, 20}] (* Harvey P. Dale, Feb 21 2013 *)

PROG

(PARI) a(n)=(10^(n+1)-7)/3 \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A051200.

Sequence in context: A029813 A138697 A186071 * A123568 A111675 A142495

Adjacent sequences:  A033172 A033173 A033174 * A033176 A033177 A033178

KEYWORD

nonn,easy

AUTHOR

Jan Jensen (dorul(AT)post6.tele.dk)

STATUS

approved

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Last modified December 7 23:55 EST 2016. Contains 278902 sequences.