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 A138339 #7 Mar 19 2013 12:12:45 %S A138339 0,7,4,12 %N A138339 Smallest index in A138343 which starts a plateau of n consecutive integers. %C A138339 The sequence provides an indication of regions of nearly no improvements of the sequence of convergents to Pi when measured by the count of correct digits after rounding. A "plateau" of n consecutive integers is defined by a(n) = j such that A138343(j) = A138343(j+n-1) and such that none of the intermediate A138343 with index j+1 up to j+n-2 drop below this level. %e A138339 a(3)=4 because the A138343(4) to A138343(6) are the earliest plateau of length 3. %e A138339 The fact that there is a local maximum at A138343(5)=9 above the plateau is consistent with the definition. %Y A138339 Cf. A138335, A138336, A138337, A138343. %K A138339 nonn,less,base,bref %O A138339 1,2 %A A138339 _Artur Jasinski_, Mar 16 2008 %E A138339 Definition and values adapted to redefined A138343 - _R. J. Mathar_, Oct 01 2009