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 A054868 Sum of bits of sum of bits of n: a(n) = wt(wt(n)). 4
 0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 1, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 1, 2, 1, 2, 2, 2, 1, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,8 COMMENTS a(n) = A000120(A000120(n)). LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 R. Bellman and H. N. Shapiro, On a problem in additive number theory, Annals Math., 49 (1948), 333-340. Michael Gilleland, Some Self-Similar Integer Sequences EXAMPLE a(127) = 3 since 127 in base 2 is 1111111, whose sum of bits is 7 and 7 in base 2 is 111, whose sum of bits is 3 PROG (PARI) a(n) = norml2(binary(norml2(binary(n))))  \\ Michel Marcus, May 25 2013 (Haskell) a054868 = a000120 . a000120  -- Reinhard Zumkeller, Mar 31 2015 CROSSREFS Cf. A000120, A089224. Sequence in context: A319608 A230850 A072085 * A065081 A212185 A270928 Adjacent sequences:  A054865 A054866 A054867 * A054869 A054870 A054871 KEYWORD nonn AUTHOR Jeffrey Shallit, May 15 2000 STATUS approved

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Last modified April 16 07:59 EDT 2021. Contains 343030 sequences. (Running on oeis4.)