A103673 - OEIS

A103673

If in binary representation n! contains 5! then 1 else 0.

0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

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OFFSET

0,1

COMMENTS

a(A103676(n)) = 1, a(A103677(n)) = 0.

Conjecture: a(n) = 1 for n > 65. -Charles R Greathouse IV,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>119, my(e=valuation(n, 2), e1=valuation((n>>=e)+1, 2)); n>>=e1; if(e>2 && e1>3, return(1))); 0 \\Charles R Greathouse IV,Apr 07 2013

CROSSREFS

Cf.A102730,A036603,A007088,A000142,A103674,A103675.

Sequence in context:A296210 A368990 A094912*A028862 A011673 A361463

Adjacent sequences:A103670 A103671 A103672*A103674 A103675 A103676

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller,Feb 12 2005

STATUS

approved