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%I #28 Jan 27 2024 07:51:41
%S 111,222,333,444,555,666,777,888,999,1110,1221,1332,1443,1554,1665,
%T 1776,1887,1998,2109,2220,2331,2442,2553,2664,2775,2886,2997,3108,
%U 3219,3330,3441,3552,3663,3774,3885,3996,4107,4218,4329,4440,4551,4662,4773,4884,4995,5106
%N a(n) = 111*n.
%C The reference contains also sequences A102807, A109344, A075415, and A109492.
%H Vincenzo Librandi, <a href="/A177769/b177769.txt">Table of n, a(n) for n = 1..10000</a>
%H Émile Fourrey, <a href="https://gallica.bnf.fr/ark:/12148/bpt6k875411n/f21.item">Le nombre 37</a>, Récreations arithmétiques, 1899 and later, Vuibert, Paris, page 11.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F G.f.: 111*x/(x-1)^2.
%F a(n) = 2*a(n-1) - a(n-2).
%F a(n) = a(n-1) + 111.
%F E.g.f.: 111*x*exp(x). - _Stefano Spezia_, Sep 15 2023
%o (Magma) [111*n: n in [1..50]]; // _Vincenzo Librandi_, Aug 04 2011
%Y Cf. A075415, A102807, A109344, A109492.
%K nonn,easy
%O 1,1
%A _Paul Curtz_, May 13 2010
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