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 A103674 #22 Jul 28 2025 03:12:46 %S A103674 0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,1,1,1,0, %T A103674 0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,0,0, %U A103674 0,0,0,1,0,0,1,0,0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1,1,0,0,0,1,0,0,1,0,0 %N A103674 If in binary representation n! contains 6! then 1 else 0. %C A103674 Conjecture: a(n) = 1 for n > 802. - _Charles R Greathouse IV_, Apr 07 2013 %C A103674 Conjecture checked up to n <= 5*10^5. - _Giovanni Resta_, Apr 07 2013 %H A103674 Amiram Eldar, <a href="/A103674/b103674.txt">Table of n, a(n) for n = 0..1000</a> %H A103674 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>. %H A103674 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>. %H A103674 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>. %F A103674 a(A103678(n)) = 1, a(A103679(n)) = 0. %o A103674 (PARI) a(n)=n=n!;while(n>719, my(e=valuation(n,2),e1=valuation((n>>=e)+1,2)); n>>=e1; if(e>3 && e1==1 && bitand(n,31)==22, return(1))); 0 \\ _Charles R Greathouse IV_, Apr 07 2013 %Y A103674 Cf. A000142, A007088, A036603, A102730, A103673, A103675, A103678, A103679. %K A103674 nonn,base %O A103674 0,1 %A A103674 _Reinhard Zumkeller_, Feb 12 2005