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 A137671 a(n+1) = number of preceding terms having in binary representation the same number of ones as a(n). 4
 1, 1, 2, 3, 1, 4, 5, 2, 6, 3, 4, 7, 1, 8, 9, 5, 6, 7, 2, 10, 8, 11, 3, 9, 10, 11, 4, 12, 12, 13, 5, 14, 6, 15, 1, 13, 7, 8, 14, 9, 16, 15, 2, 16, 17, 17, 18, 19, 10, 20, 21, 11, 12, 22, 13, 14, 15, 3, 23, 4, 18, 24, 25, 16, 19, 17, 26, 18, 27, 5, 28, 19, 20, 29, 6, 30, 7, 21, 22, 23, 8 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS A137672(n) = A000120(a(a(n)); a(A137673(n)) = n and a(m) < n for m < A137673(n). a(n) = 1 iff a(n-1) = 2^k - 1: a(A137674(n)) = 1. LINKS R. Zumkeller, Table of n, a(n) for n = 1..10000 EXAMPLE n=4: a(3) = 2 = '10', A000120(2) = 1, therefore: a(4) = #{a(1)=1='1', a(2)=1, a(3)=2='10'} = 3; n=5: a(4) = 3 = '11', A000120(3) = 2, therefore: a(5) = #{a(4)} = 1; n=6: a(5) = 1 = '1', A000120(1) = 1, therefore: a(6) = #{a(1)=1='1', a(2)=1, a(3)=2='10', a(5)} = 4. CROSSREFS Cf. A000120. Sequence in context: A092942 A131225 A221919 * A026370 A078446 A055447 Adjacent sequences:  A137668 A137669 A137670 * A137672 A137673 A137674 KEYWORD nonn AUTHOR Reinhard Zumkeller, Feb 05 2008 STATUS approved

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