This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A143344 #15 Feb 06 2019 23:54:32 %S A143344 1,3,4,6,7,8,10,11,12,13,14,16,17,18,19,20,21,23,24,25,26,27,28,29,31, %T A143344 32,33,34,35,36,37,38,39,41,42,43,44,45,46,47,48,49,50,52,53,54,55,56, %U A143344 57,58,59,60,61,62,64,65,66,67,68,69,70,71,72,73,74,75,77 %N A143344 First differences of A022941. %C A143344 This is (essentially) the sequence c() mentioned in the definition of A022941. %H A143344 Nathaniel Johnston, <a href="/A143344/b143344.txt">Table of n, a(n) for n = 1..10000</a> %p A143344 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(c[n],n=1..70); # _Nathaniel Johnston_, May 01 2011 %o A143344 (Haskell) %o A143344 import Data.List (delete) %o A143344 a143344 n = a143344_list !! (n-1) %o A143344 a143344_list = zipWith (-) (tail a022941_list) a022941_list %o A143344 -- _Reinhard Zumkeller_, May 17 2013 %Y A143344 Cf. A022941, A156031. %K A143344 nonn,easy %O A143344 1,2 %A A143344 _N. J. A. Sloane_, Nov 01 2009 %E A143344 a(26), a(27) corrected by _Nathaniel Johnston_, May 01 2011