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 A137427 #5 Oct 03 2015 22:56:59 %S A137427 1,3,6,7,3,2,1,3,7,38,1,13,65,79,94,95,7,114,133,138,159,181,51,210, %T A137427 211,237,15,247,69,34,337,339,93,406,1,442,479,517,139,566,607,649, %U A137427 173,703,177,754,89,201,805,807,858,871,231,930,985,111,66,1114,1173,33,1249 %N A137427 Squarefree part of partial sum of squarefree part of n. %C A137427 Core(partial sum(core(n))) where "core" means "squarefree part." %F A137427 a(n)=A007913(A069891(n)). - _R. J. Mathar_, Apr 23 2008 %e A137427 a(35) = 1 because A007913( A069891(35) ) = A007913(441) = A007913(21^2) = 1. %p A137427 A007913 := proc(n) local a,f ; a := 1 ; for f in ifactors(n)[2] do if op(2,f) mod 2 <> 0 then a := a*op(1,f) ; fi ; od: a ; end: A069891 := proc(n) add( A007913(k),k=1..n) ; end: A137427 := proc(n) A007913(A069891(n)) ; end: seq(A137427(n),n=1..100) ; # _R. J. Mathar_, Apr 23 2008 %Y A137427 Cf. A007913, A069891. %K A137427 easy,nonn %O A137427 1,2 %A A137427 _Jonathan Vos Post_, Apr 17 2008 %E A137427 Edited and extended by _R. J. Mathar_, Apr 23 2008