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A079948 First differences of A079000. 4
3, 2, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Alternate description of sequence: start with a(1)=3; apply 1->2, 2->11, 3->21; iterate. - Matthew Vandermast, Mar 08 2003

REFERENCES

N. J. A. Sloane, Seven Staggering Sequences, in Homage to a Pied Puzzler, E. Pegg Jr., A. H. Schoen and T. Rodgers (editors), A. K. Peters, Wellesley, MA, 2009, pp. 93-110.

LINKS

Table of n, a(n) for n=1..105.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, J. Integer Seqs., Vol. 6 (2003), #03.2.2.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, arXiv:math/0305308 [math.NT], 2003.

N. J. A. Sloane, Seven Staggering Sequences.

FORMULA

After first two terms, a run of length 3*2^k 1's followed by a run of length 3*2^k 2's, for k = 0, 1, ...

a(n) = floor(log_2(8*(floor((n+3)/3))/3)) - floor(log_2(floor((n+3)/3))) for n>2; with a(1)=3 and a(2)=2. - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 22 2003

Also a(n) = A079882(A002264(n+3)) for n>2, where A002264=floor(n/3). - Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Feb 22 2003

MATHEMATICA

b[1] = 1; b[n_] := (k = Floor[Log[2, (n+3)/6]]; j = n - (9*2^k-3); 12*2^k - 3 + 3*j/2 + Abs[j]/2); Array[b, 106] // Differences (* Jean-Fran├žois Alcover, Sep 02 2018 *)

CROSSREFS

Sequence in context: A072115 A210650 A218754 * A257657 A106689 A027082

Adjacent sequences:  A079945 A079946 A079947 * A079949 A079950 A079951

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 22 2003

STATUS

approved

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Last modified October 18 08:08 EDT 2019. Contains 328146 sequences. (Running on oeis4.)