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A153848 Repeat 21. 1

%I

%S 21,2121,212121,21212121,2121212121,212121212121,21212121212121,

%T 2121212121212121,212121212121212121,21212121212121212121,

%U 2121212121212121212121,212121212121212121212121,21212121212121212121212121,2121212121212121212121212121

%N Repeat 21.

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (101,-100).

%F a(n) = (10^(2*n)-1)*21/99.

%p a:= n-> parse(cat(21$n)):

%p seq(a(n), n=1..20); # _Alois P. Heinz_, Jun 16 2021

%o (PARI) g2(n) = (10^(2*n)-1)*1*21/99 for(x=1,25,print1(g2(x),","))

%Y Cf. A177090.

%K nonn,easy

%O 1,1

%A _Cino Hilliard_, Jan 02 2009

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Last modified October 18 03:25 EDT 2021. Contains 348065 sequences. (Running on oeis4.)