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A297777
Number of distinct runs in base-9 digits of n.
3
1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 2, 2, 3, 3, 3, 3
OFFSET
1,9
COMMENTS
Every positive integers occurs infinitely many times. See A297770 for a guide to related sequences.
LINKS
EXAMPLE
6643 in base-9: 1,0,1,0,1; five runs, of which 2 are distinct, so that a(6643) = 2.
MATHEMATICA
b = 9; s[n_] := Length[Union[Split[IntegerDigits[n, b]]]]
Table[s[n], {n, 1, 200}]
CROSSREFS
Cf. A043561 (number of runs, not necessarily distinct), A297770.
Sequence in context: A043560 A276034 A111626 * A043536 A043561 A297778
KEYWORD
nonn,base,easy
AUTHOR
Clark Kimberling, Jan 29 2018
STATUS
approved