cp's OEIS Frontend

A242645 a(n) = concatenation of decimal expansions of powers of 11 (in decreasing order).

%I A242645 #8 May 24 2014 20:19:42
%S A242645 1,111,121111,1331121111,146411331121111,161051146411331121111,
%T A242645 1771561161051146411331121111,194871711771561161051146411331121111,
%U A242645 214358881194871711771561161051146411331121111,2357947691214358881194871711771561161051146411331121111
%N A242645 a(n) = concatenation of decimal expansions of powers of 11 (in decreasing order).
%C A242645 A068704(11) (presently unknown) is either 0, if every term here is composite, or the index of the first prime in the sequence.
%H A242645 Alois P. Heinz, <a href="/A242645/b242645.txt">Table of n, a(n) for n = 0..42</a>
%F A242645 a(n) is the concatenation of 11^n, 11^(n-1), ..., 121, 11, 1.
%p A242645 a:= proc(n) option remember;
%p A242645       `if`(n=0, 1, parse(cat(11^n, a(n-1))))
%p A242645     end:
%p A242645 seq(a(n), n=0..10);  # _Alois P. Heinz_, May 24 2014
%Y A242645 Cf. A068704, A242646.
%K A242645 nonn,base
%O A242645 0,2
%A A242645 _N. J. A. Sloane_, May 23 2014