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 A120251 #1 Sep 29 2006 03:00:00
%S A120251 0,0,1,0,2,1,3,0,1,2,5,1,8,3,2,0,13,1,21,2,3,5,34,1,3,8,1,3,55,2,89,0,
%T A120251 5,13,5,1,144,21,8,2,233,3,377,5,2,34,610,1,4,3,13,8,987,1,8,3,21,55,
%U A120251 1597,2,2584,89,3,0,13,5,4181,13,34,5,6765,1,10946,144,3,21,7,8,17711,2
%N A120251 A120249[n] modulo A120250[n].
%C A120251 a[n] = 0 precisely when n is a power of 2.
%F A120251 a[n] = Mod[A120249[n], A120250[n]]
%e A120251 a[n] = A120249[2646] modulo A120250[2646] = 42 modulo 19 = 4
%t A120251 Table[If[n == 1, 0, (fl = FactorInteger[n]; pq = Table[1, {i, 1, PrimePi[Last[fl][[1]]]}]; While[Length[fl] > 0, pp = First[fl]; fl = Drop[fl, 1]; pq[[PrimePi[pp[[1]]]]] = pp[[2]] + 1;]; Mod[Numerator[FromContinuedFraction[pq]], Denominator[FromContinuedFraction[pq]]])], {n, 1, 80}]
%Y A120251 Cf. Corresponding denominators in A120250.
%K A120251 frac,hard,nonn
%O A120251 1,5
%A A120251 Joseph Biberstine (jrbibers(AT)indiana.edu), Jun 12 2006