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A156351 a(n)=sum_{k=1..n} (-1)^K(k+1)*(K(k+1)-K(k)) where K(k)=A000002(k) 1
1, 1, 2, 2, 3, 4, 5, 5, 6, 7, 7, 8, 8, 9, 10, 10, 11, 11, 12, 13, 14, 14, 15, 16, 17, 17, 18, 18, 19, 20, 20, 21, 22, 23, 23, 24, 25, 25, 26, 26, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 34, 35, 35, 36, 37, 37, 38, 38, 39, 40, 41, 41, 42, 43, 43, 44, 44, 45, 46, 46, 47, 48, 49, 49 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

a(n)=1 plus the number of symbol changes in the first n terms of A078880. [From Jean-Marc Fedou and Gabriele Fici (fici(AT)i3s.unice.fr), Mar 18 2010]

LINKS

J.M. Fedou and G. Fici, Some remarks on differentiable sequences and recursivity, Journal of Integer Sequences 13(3): Article 10.3.2 (2010). [From Jean-Marc Fedou and Gabriele Fici (fici(AT)i3s.unice.fr), Mar 18 2010]

FORMULA

n-A054353(a(n))=1 if n is in A078649, n-A054353(a(n))=0 otherwise. A078649(n+1-a(n))-n takes values among {0,1,2,3}.

CROSSREFS

Sequence in context: A057062 A065855 A034137 * A057561 A064726 A057359

Adjacent sequences:  A156348 A156349 A156350 * A156352 A156353 A156354

KEYWORD

nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 08 2009

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Last modified February 14 22:09 EST 2012. Contains 205669 sequences.