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 A077682 #27 Aug 10 2025 17:01:47 %S A077682 6,61,62,65,66,67,69,601,602,606,607,609,610,611,613,614,615,617,618, %T A077682 619,622,623,626,627,629,631,633,634,635,638,641,642,643,645,646,647, %U A077682 649,651,653,654,655,658,659,661,662,663,665,667,669,670,671,673,674 %N A077682 Squarefree numbers beginning with 6. %C A077682 Intersection of A005117 and A217399. - _Michel Marcus_, Sep 14 2013 %C A077682 Lower density is 1/(10*Pi^2), upper density is 20/(21*Pi^2). - _Charles R Greathouse IV_, Nov 05 2017 %H A077682 Muniru A Asiru, <a href="/A077682/b077682.txt">Table of n, a(n) for n = 1..6761</a> %p A077682 with(numtheory): select(issqrfree,[seq(seq(6*10^n+k,k=0..10^n-1),n=0..3)]); # _Muniru A Asiru_, Nov 22 2018 %t A077682 Select[Range[1000],SquareFreeQ[#]&&First[IntegerDigits[#]]==6&] (* _Harvey P. Dale_, May 19 2012 *) %o A077682 (PARI) is(n)=n>5 && digits(n)[1]==6 && issquarefree(n) \\ _Charles R Greathouse IV_, Nov 05 2017 %Y A077682 Cf. A077677, A077678, A077679, A077680, A077681, A077683, A077684, A077685. %Y A077682 Cf. A005117, A217399. %K A077682 base,easy,nonn %O A077682 1,1 %A A077682 _Amarnath Murthy_, Nov 16 2002 %E A077682 More terms from _Sascha Kurz_, Jan 28 2003