A107680 - OEIS

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A107680

Repeating k-th ternary repunit 2^k times for k>0.

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.