cp's OEIS Frontend

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.

A069186 Numbers n such that core(n)=floor(sqrt(n)), where core(x)=A007913(x) is the squarefree part of x and floor(sqrt(x))=A000196(x).

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%I A069186 #17 Apr 14 2019 06:56:59
%S A069186 1,8,12,63,224,240,575,1224,1260,2303,3968,6399,14399,20448,20592,
%T A069186 28223,38024,38220,50175,65024,65280,82943,104328,104652,129599,
%U A069186 159200,159600,193599,233288,233772,278783,330624,389375,455624
%N A069186 Numbers n such that core(n)=floor(sqrt(n)), where core(x)=A007913(x) is the squarefree part of x and floor(sqrt(x))=A000196(x).
%C A069186 Apart from 1, numbers of the form x*y^2 for y >= 2, where x is squarefree and is either y^2-2 or y^2-1. - _Robert Israel_, Apr 11 2019
%H A069186 Robert Israel, <a href="/A069186/b069186.txt">Table of n, a(n) for n = 1..10000</a>
%p A069186 select(numtheory:-issqrfree, [1, seq(seq(b^2+j,j=-2..-1),b=2..100)]); # _Robert Israel_, Apr 11 2019
%o A069186 (PARI) isok(n) = core(n) == sqrtint(n); \\ _Michel Marcus_, Apr 12 2019
%Y A069186 Cf. A000196, A007913.
%K A069186 easy,nonn
%O A069186 1,2
%A A069186 _Benoit Cloitre_, Apr 14 2002
%E A069186 Name edited by _Robert Israel_, Apr 12 2019