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 A056980 Number of blocks of {1, 1, 0} in binary expansion of n. 11
 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,54 COMMENTS a(n) = A213629(n,6) for n > 5. - Reinhard Zumkeller, Jun 17 2012 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 Eric Weisstein's World of Mathematics, DigitBlock FORMULA a(2n) = a(n) + [n congruent to 3 mod 4], a(2n+1) = a(n). - Ralf Stephan, Aug 22 2003 MATHEMATICA a[1] = a[2] = 0; a[n_] := a[n] = If[OddQ[n], a[(n - 1)/2], a[n/2] + Boole[Mod[n/2, 4] == 3]]; Table[a[n], {n, 1, 102}] (* Jean-François Alcover, Oct 22 2012, after Ralf Stephan *) PROG (Haskell) import Data.List (tails, isPrefixOf) a056980 = sum . map (fromEnum . ([0, 1, 1] `isPrefixOf`)) .                     tails . a030308_row -- Reinhard Zumkeller, Jun 17 2012 (PARI) a(n) = hammingweight(bitnegimply(bitand(n>>1, n>>2), n)); vector(102, i, a(i))  \\  Gheorghe Coserea, Sep 07 2015 CROSSREFS Cf. A014082, A056974, A056975, A056976, A056977, A056978, A056979, A056980. Sequence in context: A176046 A172090 A037912 * A268643 A005094 A121372 Adjacent sequences:  A056977 A056978 A056979 * A056981 A056982 A056983 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified May 29 03:06 EDT 2020. Contains 334696 sequences. (Running on oeis4.)