A103681 - OEIS

A103681

Numbers m such that in binary representation m! doesn't contain 7!.

0, 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73

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OFFSET

1,3

COMMENTS

Complement of A103680: A103675(a(n))=0, A103675(A103680(n))=1.

Last term is probably 5153, since all numbers from 5154 to 5*10^5 do not belong to the sequence. - Giovanni Resta, Apr 07 2013

LINKS

Table of n, a(n) for n=1..72.

Index entries for sequences related to factorial numbers

Index entries for sequences related to binary expansion of n

PROG

(PARI) is(n)=n=n!; while(n>5039, my(e=valuation(n, 2), e1=valuation((n>>=e)+1, 2)); n>>=e1; if(e>3 && e1==2 && bitand(n, 127)==78, return(0))); 1 \\ Charles R Greathouse IV, Apr 07 2013

CROSSREFS

Cf. A102730, A036603, A007088, A000142, A103677, A103679.

Sequence in context: A297165 A245606 A269864 * A367696 A319824 A039265

Adjacent sequences: A103678 A103679 A103680 * A103682 A103683 A103684

KEYWORD

base,nonn

AUTHOR

Reinhard Zumkeller, Feb 12 2005

STATUS

approved