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A164898
First differences of numbers having only odd digits in their decimal representation.
3
2, 2, 2, 2, 2, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 112, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 112, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12, 2, 2, 2, 2, 12
OFFSET
1,1
COMMENTS
a(n) = A014261(n+1) - A014261(n);
all terms are of the form (10^k + 8)/9, see A047855;
a(n) > 2 iff A014261(n) mod 10 = 9.
LINKS
MAPLE
R[1]:= [1, 3, 5, 7, 9]:
for d from 2 to 3 do
R[d]:= map(t -> seq(10*t+i, i=[1, 3, 5, 7, 9]), R[d-1])
od:
B:= map(op, [seq(R[d], d=1..3)]):
B[2..-1]-B[1..-2]; # Robert Israel, Jan 24 2022
MATHEMATICA
Differences[Select[Range[1000], Count[IntegerDigits[#], _?EvenQ]==0&]] (* Harvey P. Dale, Jan 03 2019 *)
CROSSREFS
Cf. A014261.
Sequence in context: A252375 A339170 A257773 * A100801 A194310 A306227
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Aug 30 2009
STATUS
approved