

A156253


Least k such that A054353(k)>=n


7



1, 2, 2, 3, 3, 4, 5, 6, 6, 7, 8, 8, 9, 9, 10, 11, 11, 12, 12, 13, 14, 15, 15, 16, 17, 18, 18, 19, 19, 20, 21, 21, 22, 23, 24, 24, 25, 26, 26, 27, 27, 28, 29, 30, 30, 31, 32, 33, 33, 34, 35, 35, 36, 36, 37, 38, 38, 39, 39, 40, 41, 42, 42, 43, 44, 44, 45, 45, 46, 47, 47, 48, 49, 50
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS

a(n)=1 plus the number of symbol changes in the first n terms of A000002. [From JeanMarc Fedou and Gabriele Fici, Mar 18 2010]


LINKS

Table of n, a(n) for n=1..74.
J.M. Fedou and G. Fici, Some remarks on differentiable sequences and recursivity, Journal of Integer Sequences 13(3): Article 10.3.2 (2010).


FORMULA

a(n) should be asymptotic to 2n/3.
Length of nth run of the sequence = A000002(n) [From Benoit Cloitre, Feb 19 2009]


MATHEMATICA

a2 = {1, 2, 2}; Do[ a2 = Join[a2, {1 + Mod[n  1, 2]}], {n, 3, 80}, {i, 1, a2[[n]]}]; a3 = Accumulate[a2]; a[1] = 1; a[n_] := a[n] = For[k = a[n  1], True, k++, If[a3[[k]] >= n, Return[k]]]; Table[a[n], {n, 1, 80}] (* JeanFrançois Alcover, Jun 18 2013 *)


CROSSREFS

Sequence in context: A255573 A062298 A116579 * A265436 A060151 A097330
Adjacent sequences: A156250 A156251 A156252 * A156254 A156255 A156256


KEYWORD

nonn,changed


AUTHOR

Benoit Cloitre, Feb 07 2009


STATUS

approved



