A103674 If in binary representation n! contains 6! then 1 else 0.

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, 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, 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

Offset

0,1

Comments

a(A103678(n)) = 1, a(A103679(n)) = 0.

Conjecture: a(n) = 1 for n > 802. - Charles R Greathouse IV, Apr 07 2013

Conjecture checked up to n <= 5*10^5. - Giovanni Resta, Apr 07 2013

Links

Table of n, a(n) for n=0..104.

Index entries for characteristic functions

Index entries for sequences related to factorial numbers

Index entries for sequences related to binary expansion of n

Prog

(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

Crossrefs

Cf. A102730, A036603, A007088, A000142, A103673, A103675.

Sequence in context: A135500 A023972 A185016 * A358842 A358758 A185708

Adjacent sequences: A103671 A103672 A103673 * A103675 A103676 A103677

Keyword

nonn,base

Author

Reinhard Zumkeller, Feb 12 2005

Status

approved