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A030340
a(n)=(# 1's)-(# 2's) in first n terms of A003137.
2
1, 0, 1, 1, 2, 3, 4, 3, 2, 2, 1, 2, 1, 0, 1, 1, 1, 2, 2, 3, 4, 4, 3, 4, 5, 5, 6, 7, 8, 9, 10, 9, 10, 9, 9, 10, 9, 10, 11, 10, 9, 8, 8, 8, 7, 7, 8, 7, 7, 6, 5, 6, 6, 5, 6, 7, 6, 7, 6, 5, 4, 4, 3, 2, 3, 2, 1, 0, 1, 1, 1, 1, 2, 2, 2, 3, 4, 4, 4, 3, 4, 4, 5, 5
OFFSET
1,5
COMMENTS
This sequence is nonnegative: in any group of numbers with the same number of digits, the number with a 1 in a particular position always occurs before the number with a 2 in that position. In fact, 0's only occur on the last digits of (3^N)-1, where N is an integer, not the sequence index - Larry Reeves (larryr(AT)acm.org), Sep 25 2000
LINKS
PROG
(Haskell)
a030340 n = a030340_list !! (n-1)
a030340_list = scanl1
(\u v -> u + fromEnum (v == 1) - fromEnum (v == 2)) a003137_list
-- Reinhard Zumkeller, Feb 21 2013
CROSSREFS
Cf. A030339.
Sequence in context: A260644 A073791 A350862 * A122453 A017849 A134536
KEYWORD
nonn,base
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Sep 25 2000
Some data corrected by Reinhard Zumkeller, Feb 21 2013
STATUS
approved