%I A028881
%S A028881 2,9,18,29,42,57,74,93,114,137,162,189,218,249,282,317,354,393,434,
%T A028881 477,522,569,618,669,722,777,834,893,954,1017,1082,1149,1218,1289,
%U A028881 1362,1437,1514,1593,1674,1757,1842,1929,2018,2109,2202,2297,2394
%N A028881 n^2 - 7.
%H A028881 P. De Geest, <a href="http://www.worldofnumbers.com/consemor.htm">Palindromic 
               Quasipronics of the form n(n+x)</a>
%F A028881 a(n)=2*n+a(n-1)+3 (with a(1)=2) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), 
               Nov 07 2009]
%e A028881 For n=2, a(2)=2*2+2+3=9; n=3, a(3)=2*3+9+3=18; n=4, a(4)=2*4+18+3=29 
               [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 07 2009]
%t A028881 s=0;lst={};Do[s+=n;If[(s-7)>0,AppendTo[lst,s-7]],{n,1,6!,2}];lst [From 
               Vladimir Orlovsky (4vladimir(AT)gmail.com), May 25 2009]
%o A028881 (Other) SAGE:[lucas_number2(2,n,3-n) for n in xrange(2,49)]# [From Zerinvary 
               Lajos (zerinvarylajos(AT)yahoo.com), Mar 12 2009]
%Y A028881 Sequence in context: A126082 A083707 A103256 this_sequence A083708 A037421 
               A083423
%Y A028881 Adjacent sequences: A028878 A028879 A028880 this_sequence A028882 A028883 
               A028884
%K A028881 nonn,new
%O A028881 3,1
%A A028881 Patrick De Geest (pdg(AT)worldofnumbers.com)