%I #7 Apr 04 2016 18:53:58
%S 1,2,5,8,12,17,22,28,35,42,50,58,68,77,88,98,111,122,136,148,163,177,
%T 193,208,225,241,259,277,296,315,335,355,376,398,420,443,466,490,514,
%U 539,565,591,618,645,673,701,730,760,790,821,852,884,916
%N a(n) = a(n-2) + c(n-1) for n >= 3, a( ) increasing, given a(1)=1, a(2)=2; where c( ) is complement of a( ).
%H Ivan Neretin, <a href="/A022942/b022942.txt">Table of n, a(n) for n = 1..10000</a>
%t Fold[Append[#1, #1[[-2]] + Complement[Range[Max@#1 + 2], #1][[#2]]] &, {1, 2}, Range[2, 52]] (* _Ivan Neretin_, Apr 04 2016 *)
%Y Cf. A005228 and references therein.
%K nonn
%O 1,2
%A _Clark Kimberling_