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 A221470 #10 Jan 18 2013 19:19:43
%S A221470 1,5,3,7,15,287,191,127,223,159,143,95,63,47,31,27,703,6471,6383,4255,
%T A221470 6887,4591,50427,47867,31911,77671,161439,113383,239231,159487,
%U A221470 1027431,974079,730559,487039,432923,288615,270271,3041391,9158655,6416623,16786431,12589823
%N A221470 Least m such that the Collatz (3x+1) iteration of m has exactly n increasing peak values.
%C A221470 Sequence A221469 lists the number of increasing peaks.
%H A221470 T. D. Noe, <a href="/A221470/b221470.txt">Table of n, a(n) for n = 0..60</a>
%e A221470 The Collatz iteration starting at 7 is (7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1), which has 3 increasing peaks: 22, 34, and 52. No number smaller than 7 has 3 increasing peaks. Hence, a(3) = 7.
%t A221470 Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; nn = 20; t = Table[0, {nn}]; found = 0; n = 0; While[found < nn, n++; c = Collatz[n]; cnt = 0; mx = n; Do[If[k > mx, cnt++; mx = k], {k, c}]; If[cnt > 0 && cnt <= nn && t[[cnt]] == 0, t[[cnt]] = n; found++]]; Join[{1}, t]
%o A221470 (Haskell)
%o A221470 a221470 = (+ 1 ) . fromJust . (`elemIndex` (map a221469 [1..]))
%o A221470 -- _Reinhard Zumkeller_, Jan 18 2013
%Y A221470 Cf. A070165 (Collatz trajectory of n), A221469.
%K A221470 nonn
%O A221470 0,2
%A A221470 _T. D. Noe_, Jan 17 2013