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A117640 Concatenation of first n numbers in base 4. 0
1, 12, 123, 12310, 1231011, 123101112, 12310111213, 1231011121320, 123101112132021, 12310111213202122, 1231011121320212223, 123101112132021222330, 12310111213202122233031 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Quaternary analogue of A047778 Concatenation of first n numbers in binary. See also A054635 Champernowne sequence: write n in base 3 and juxtapose.

FORMULA

a(n) = a(n-1)*4^(1+floor[log4(n)])+n.

CROSSREFS

Cf. A047778, A054635.

Sequence in context: A141266 A083429 A077306 * A074158 A071269 A061088

Adjacent sequences:  A117637 A117638 A117639 * A117641 A117642 A117643

KEYWORD

base,easy,nonn

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 27 2006

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Last modified February 17 18:34 EST 2012. Contains 206074 sequences.