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 A002281 a(n) = 7(10^n - 1)/9. 30

%I

%S 0,7,77,777,7777,77777,777777,7777777,77777777,777777777,7777777777,

%T 77777777777,777777777777,7777777777777,77777777777777,

%U 777777777777777,7777777777777777,77777777777777777,777777777777777777,7777777777777777777

%N a(n) = 7(10^n - 1)/9.

%H Ivan Panchenko, <a href="/A002281/b002281.txt">Table of n, a(n) for n = 0..200</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).

%F a(n) = 10*a(n-1)+7 with n>0, a(0)=0. - _Paolo P. Lava_, Jan 23 2009

%F a(n) = A178634(n) / A002283(n). - _Reinhard Zumkeller_, May 31 2010

%F a(n) = a(n-1)+7*10^(n-1) with n>0, a(0)=0; also: a(n) = 11*a(n-1)-10*a(n-2) with n>1, a(0)=0, a(1)=7. - _Vincenzo Librandi_, Jul 22 2010

%F G.f.: 7*x/((x-1)*(10*x-1)). - _Colin Barker_, Jan 24 2013

%F a(n) = 7*A002275(n). - _Wesley Ivan Hurt_, Mar 24 2015

%p A002281:=n->7*(10^n-1)/9: seq(A002281(n), n=0..30); # _Wesley Ivan Hurt_, Mar 24 2015

%t LinearRecurrence[{11,-10},{0,7},25] (* _Robert G. Wilson v_, Jul 06 2013 *)

%o (MAGMA) [7*(10^n-1)/9 : n in [0..30]]; // _Wesley Ivan Hurt_, Mar 24 2015

%o (PARI) a(n)=7*(10^n-1)/9 \\ _Charles R Greathouse IV_, Sep 24 2015

%Y Cf. A002275, A002276, A002277, A002278, A002279, A002280, A002282, A178630.

%K easy,nonn

%O 0,2

%A _N. J. A. Sloane_

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Last modified May 31 16:29 EDT 2020. Contains 334748 sequences. (Running on oeis4.)