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A004743 Numbers n such that binary expansion does not contain 110. 9
0, 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 15, 16, 17, 18, 19, 20, 21, 23, 31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 47, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 79, 80, 81, 82, 83, 84, 85, 87, 95, 127, 128, 129, 130, 131, 132, 133, 135, 136, 137, 138, 139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Index entries for 2-automatic sequences.

PROG

(PARI) is(n)=n=binary(n); for(i=3, #n, if(!n[i]&&n[i-2]&&n[i-1], return(0))); 1 \\ Charles R Greathouse IV, Mar 26 2013

(PARI) is(n)=while(n>5, if(bitand(n, 7)==6, return(0)); n>>=1); 1 \\ Charles R Greathouse IV, Feb 11 2017

(Haskell)

a004743 n = a004743_list !! (n-1)

a004743_list = filter f [0..] where

   f x  = x < 4 || x `mod` 8 /= 6 && f (x `div` 2)

-- Reinhard Zumkeller, Jul 01 2013

CROSSREFS

Cf. A007088; A003796 (no 000), A004745 (no 001), A004746 (no 010), A004744 (no 011), A003754 (no 100), A004742 (no 101), A003726 (no 111).

Sequence in context: A023748 A324845 A107686 * A333764 A333943 A334273

Adjacent sequences:  A004740 A004741 A004742 * A004744 A004745 A004746

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 29 10:41 EDT 2020. Contains 334699 sequences. (Running on oeis4.)