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A255568 Numbers in whose binary representation there are six 1-bits more than there are nonleading 0-bits. 2
63, 191, 223, 239, 247, 251, 253, 254, 639, 703, 735, 751, 759, 763, 765, 766, 831, 863, 879, 887, 891, 893, 894, 927, 943, 951, 955, 957, 958, 975, 983, 987, 989, 990, 999, 1003, 1005, 1006, 1011, 1013, 1014, 1017, 1018, 1020, 2303, 2431, 2495, 2527, 2543, 2551, 2555 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers for which A037861(n) = -6.

Numbers in whose binary representation (A007088) the number of 1-bits = 6 + number of (nonleading) 0 bits.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16303

EXAMPLE

63 ("111111" in binary) is included because there are 0 zero-bits and six 1-bits.

191 ("10111111" in binary) is included because there is 1 zero-bit and seven 1-bits, thus there are six 1-bits more than the number of 0-bits.

PROG

(Scheme, with Antti Karttunen's IntSeq-library)

(define A255568 (MATCHING-POS 1 1 (lambda (n) (= -6 (A037861 n)))))

(Perl) use ntheory ":all"; my $bits = 0; for (1..1000) { my $o = hammingweight($_); $bits++ if ($_ & ($_-1))==0; say if $o == 6+$bits-$o; } # Dana Jacobsen, Dec 16 2015

(PARI) is(n)=2*hammingweight(n)==6+#binary(n) \\ Charles R Greathouse IV, Dec 16 2015

(PARI) for(b=3, 6, for(n=2^(2*b-1), 4^b-1, if(hammingweight(n)==3+b, print1(n", ")))) \\ Charles R Greathouse IV, Dec 16 2015

(PARI) listBBitMembers(b)=if(b%2, return([])); my(u=List()); forvec(v=vector(3+b/2, i, [0, b-1]), listput(u, sum(i=1, #v, 2^v[i])), 2); Vec(u) \\ Charles R Greathouse IV, Dec 16 2015

CROSSREFS

Cf. A007088, A037861.

The intersection of A030130 and A023689 is a finite subsequence of this sequence.

Sequence in context: A008895 A008874 A045112 * A143033 A156527 A199850

Adjacent sequences:  A255565 A255566 A255567 * A255569 A255570 A255571

KEYWORD

nonn,base,easy

AUTHOR

Antti Karttunen, Mar 11 2015

STATUS

approved

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Last modified March 4 03:53 EST 2021. Contains 341779 sequences. (Running on oeis4.)