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A098752
a(1) = 1 and a(n+1) is the least number > a(n) that begins with the last digit of a(n) and doesn't end with 0.
0
1, 11, 12, 21, 101, 102, 201, 1001, 1002, 2001, 10001, 10002, 20001, 100001, 100002, 200001, 1000001, 1000002, 2000001, 10000001, 10000002, 20000001, 100000001, 100000002, 200000001, 1000000001, 1000000002, 2000000001, 10000000001
OFFSET
1,2
COMMENTS
a(n) must be chosen with nonzero rightmost digit.
FORMULA
For n == 0 (mod 3), a(n) = 10^(n/3) + 2; for n == 1 (mod 3), n>1, a(n) = 2*10^((n-1)/3) + 1; for n == 2 (mod 3), a(n) = 10^((n+1)/3) + 1. - Sam Alexander, Jan 04 2005
From Chai Wah Wu, Jun 02 2016: (Start)
a(n) = 11*a(n-3) - 10*a(n-6) for n > 7.
G.f.: x*(1 + x + 2*x^2)*(1 + 10*x - 10*x^3 - 10*x^4)/((1 - x)*(1 - 10*x^3)*(1 + x + x^2)). (End)
a(n) = (1-sign((n-1) mod 3))*10^floor(n/3)+10^floor((n+1)/3)-sign(n mod 3)+2, for n > 1. - Wesley Ivan Hurt, Mar 06 2022
CROSSREFS
Cf. A076654.
Cf. A101233.
Sequence in context: A131363 A089185 A098754 * A240763 A231871 A192287
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, Oct 01 2004
EXTENSIONS
More terms from Sam Alexander, Jan 04 2005
More terms from David Wasserman, Feb 26 2008
STATUS
approved