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A079214
Catalan paths: numbers starting with 1 and ending with 0 where each digit is nonnegative and adjacent digits differ by 1.
4
10, 1010, 1210, 101010, 101210, 121010, 121210, 123210, 10101010, 10101210, 10121010, 10121210, 10123210, 12101010, 12101210, 12121010, 12121210, 12123210, 12321010, 12321210, 12323210, 12343210, 1010101010, 1010101210
OFFSET
1,1
COMMENTS
a(23713) cannot easily be written in decimal.
FORMULA
a(n) =A079215(n)-(10^ceiling[log_10(A079215(n))]-1)/9.
EXAMPLE
Can be constructed from A063171 by (starting from a notional leading 0) adding 1 to previous digit of a(n) if next digit of A063171 is 1 and subtracting 1 if next digit is 0: e.g. A063171(3)=1100, so digits of a(3) are 0+1=1, 1+1=2, 2-1=1 and 1-1=0 giving a(3)=1210.
CROSSREFS
Cf. A063171, A079215. a(n) has A000108(m) values with 2m digits.
Sequence in context: A071671 A075171 A106456 * A163662 A176067 A080070
KEYWORD
base,nonn
AUTHOR
Henry Bottomley, Jan 02 2003
STATUS
approved