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 A234588 #35 Sep 15 2018 02:04:31 %S A234588 1,2,4,5,9,14,8,10,18,27,17,6,11,15,29,44,19,36,54,35,21,42,23,46,25, %T A234588 50,28,55,83,112,31,62,33,66,37,72,108,71,39,78,41,82,124,45,89,134, %U A234588 88,48,96,51,101,152,53,106,160,105,57,114,59,118,61,122,184,64 %N A234588 Lexicographically earliest sequence S with property that a(n) is the a(n)-th absolute first difference of S. %C A234588 A kind of self-describing sequence. %C A234588 Recamán's sequence A005132 is also self-describing in this sense, but comes lexicographically after this one (and you have to drop the initial "0"). %C A234588 If we want S to be monotonically increasing, we get A063733. %D A234588 Eric Angelini, Posting to Sequence Fans Mailing List, Nov 26, 2010 %e A234588 If n = 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 ... %e A234588 a(n) = 1 2 4 5 9 14 8 10 18 27 17, 6 11 15 29 44 19 36 54 35 21 42 23 46 25 50 28 55 ... %e A234588 diff = 1 2 1 4 5 6 2 8 9 10 11 5 4 14 15 25 17 18 19 14 21 19 23 21 25 22 %e A234588 d-rank= 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 %e A234588 hit: * * * * * * * * * * * * * %e A234588 S is tricky to compute; the rule for a(n+1) is "always use the smallest integer not yet in S and not leading to a contradiction". %e A234588 '14' is in S and '14' says: "The 14th absolute first difference in S equals 14" -- which is true. %Y A234588 Cf. A005132, A063733. %K A234588 nonn %O A234588 1,2 %A A234588 _Eric Angelini_, Dec 31 2013 %E A234588 More terms from _Jon E. Schoenfield_, Jan 11 2014