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A107680 Repeating k-th ternary repunit 2^k times for k>0. 3
1, 1, 4, 4, 4, 4, 13, 13, 13, 13, 13, 13, 13, 13, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121, 121 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

A032924(n) = a(n) + A107681(n);

a(n) = greatest ternary repunit that is not greater than the n-th number with no 2 in ternary representation;

A081604(A107681(n)) <= A081604(a(n)) = A081604(A032924(n)) = A000523(n+1).

FORMULA

a(n) = A003462(A000523(n+1)).

EXAMPLE

k=1: A003462(1) = (3^1-1)/2 = 1, therefore a(1) = a(2^1) = 1;

k=2: A003462(2) = (3^2-1)/2 = 4, therefore a(2+1) = a(2+2) =

a(2+3) = a(2+2^2) = 4.

CROSSREFS

Cf. A007089.

Sequence in context: A190718 A035621 A046109 * A202686 A134660 A132383

Adjacent sequences:  A107677 A107678 A107679 * A107681 A107682 A107683

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 20 2005

EXTENSIONS

Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 25 2006

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Last modified February 15 03:58 EST 2012. Contains 205694 sequences.