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A004745 Numbers n such that binary expansion does not contain 001. 8
0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 32, 40, 42, 43, 44, 45, 46, 47, 48, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 80, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 104, 106, 107, 108, 109, 110 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Index entries for 2-automatic sequences.

PROG

(PARI) is(n)=n=binary(n); for(i=4, #n, if(n[i]&&!n[i-1]&&!n[i-2], return(0))); 1 \\ Charles R Greathouse IV, Mar 29 2013

(PARI) is(n)=while(n>8, if(bitand(n, 7)==1, return(0)); n>>=1); 1 \\ Charles R Greathouse IV, Feb 11 2017

(Haskell)

a004745 n = a004745_list !! (n-1)

a004745_list = filter f [0..] where

   f x  = x < 4 || x `mod` 8 /= 1 && f (x `div` 2)

-- Reinhard Zumkeller, Jul 01 2013

CROSSREFS

Cf. A007088; A003796 (no 000), A004746 (no 010), A004744 (no 011), A003754 (no 100), A004742 (no 101), A004743 (no 110), A003726 (no 111).

Sequence in context: A004774 A191845 A274375 * A158037 A287519 A246786

Adjacent sequences:  A004742 A004743 A004744 * A004746 A004747 A004748

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified February 22 23:03 EST 2019. Contains 320411 sequences. (Running on oeis4.)