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%I #25 Apr 06 2016 10:35:24
%S 1,2,5,9,15,22,30,40,51,63,76,90,106,123,141,160,180,201,224,248,273,
%T 299,326,354,383,414,446,479,513,548,584,621,659,698,739,781,824,868,
%U 913,959,1006,1054,1103,1153,1205,1258,1312,1367,1423,1480,1538
%N a(n) = a(n-1) + c(n-2) for n >= 3, a( ) increasing, given a(1)=1, a(2)=2; where c( ) is complement of a( ).
%C Except for a(2), identical to A022940. - _Ivan Neretin_, Apr 05 2016
%H Nathaniel Johnston, <a href="/A022941/b022941.txt">Table of n, a(n) for n = 1..10000</a>
%p a[1]:=1: a[2]:=2: c[1]:=3: for n from 2 to 70 do c[n]:=c[n-1]+1: for k from 1 to n do if(c[n]<=a[k])then if(c[n]=a[k])then c[n]:=c[n]+1: fi: break: fi: od: a[n+1]:=a[n]+c[n-1]: od: seq(a[n],n=1..70); # _Nathaniel Johnston_, May 01 2011
%t Fold[Append[#1, #1[[-1]] + Complement[Range[Max@#1 + 1], #1][[#2]]] &, {1, 2}, Range[50]] (* _Ivan Neretin_, Apr 04 2016 *)
%o (Haskell)
%o import Data.List (delete)
%o a022941 n = a022941_list !! (n-1)
%o a022941_list = 1 : 2 : f 2 [3..] where
%o f x (z:zs) = y : f y (delete y zs) where y = x + z
%o -- _Reinhard Zumkeller_, May 17 2013
%Y Cf. A143344 (first differences), A156031.
%Y Cf. A005228 and references therein.
%K nonn
%O 1,2
%A _Clark Kimberling_
%E a(27) inserted by _Nathaniel Johnston_, May 01 2011
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