STATUS
proposed
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editing
proposed
Equivalently, numbers n such that 9*n = 9 X n, i.e. , 8*n XOR n = 9*n. Here * stands for ordinary multiplication and X means carryless (GF(2)[X]) multiplication (A048720).
The equivalence of these three definitions follows from Lucas's theorem on binomial coefficients. - N. J. A. Sloane, Sep 01, 2010
Clearly all numbers k*2^i for 1 <= k <= 7 have this property. - N. J. A. Sloane, Sep 01, 2010
Reap[Do[If[OddQ[Binomial[9n, n]], Sow[n]], {n, 0, 400}]][[2, 1]] - _(* _Zak Seidov_, Aug 06 2010 *)
Edited with a new definition by N. J. A. Sloane, Sep 01, 2010, merging this sequence with a sequence submitted by Zak Seidov, Aug 06 2010.
approved
editing
N. J. A. Sloane and _Charles R Greathouse IV_, , <a href="/A115845/b115845.txt">Table of n, a(n) for n = 1..10000</a>
N. J. A. Sloane and _Charles R Greathouse IV, _, <a href="/A115845/b115845.txt">Table of n, a(n) for n = 1..10000</a>
The equivalence of these three definitions follows from Lucas's theorem on binomial coefficients. - _N. J. A. Sloane, _, Sep 01, 2010
Clearly all numbers k*2^i for 1 <= k <= 7 have this property. - _N. J. A. Sloane, _, Sep 01, 2010
Edited with a new definition by _N. J. A. Sloane, _, Sep 01, 2010, merging this sequence with a sequence submitted by Zak Seidov, Aug 06 2010.
N. J. A. Sloane and Charles R Greathouse IV, <a href="/A115845/b115845_1.txt">Table of n, a(n) for n = 1..10000</a>
editing
approved
a(n)/n^k is bounded (but does not tend to a limit), where k = 1.44... = A104287. - Charles R Greathouse IV, Sep 23 2012
(PARI) is(n)=!bitand(n, n<<3) \\ Charles R Greathouse IV, Sep 23 2012
approved
editing