%I A047211
%S A047211 2,4,7,9,12,14,17,19,22,24,27,29,32,34,37,39,42,44,47,49,52,54,57,59,
%T A047211 62,64,67,69,72,74,77,79,82,84,87,89,92,94,97,99,102,104,107,109,112,
%U A047211 114,117,119,122,124,127,129
%N A047211 Numbers that are congruent to {2, 4} mod 5.
%F A047211 a(n) = ( 10*n + 7 + (-1)^n ) / 4.
%F A047211 G.f.: (2+2x+x^2)/((1+x)(1-x)^2); [From Paul Barry (pbarry(AT)wit.ie), 
               Sep 11 2008]
%F A047211 a(n)=5*n-a(n-1)-4 (with a(1)=2) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), 
               Nov 22 2009]
%e A047211 For n=2, a(2)=5*2-2-4=4; n=3, a(3)=5*3-4-4=7; n=4, a(4)=5*4-7-4=9 [From 
               Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 22 2009]
%Y A047211 Sequence in context: A022840 A064995 A067839 this_sequence A087733 A065027 
               A165994
%Y A047211 Adjacent sequences: A047208 A047209 A047210 this_sequence A047212 A047213 
               A047214
%K A047211 nonn,new
%O A047211 1,1
%A A047211 N. J. A. Sloane (njas(AT)research.att.com).