OFFSET
1,19
COMMENTS
For n > 1: if A023961(n)=3 then a(n) = a(n-1) + 1, otherwise a(n) = a(n-1).
Lim_{n->infinity} a(n)/n = 1/10.
REFERENCES
G. Pólya and G. Szegő, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part Two, Chap. 4, Sect. 4, Problem 178.
EXAMPLE
a(10) = 0, a(100) = 9, a(1000) = 99, a(10000) = 990.
MATHEMATICA
fddpQ[n_]:=Module[{a, b}, {a, b}=RealDigits[Surd[n, 2], 10, 10]; a[[b+1]] == 3]; Accumulate[Table[If[fddpQ[n], 1, 0], {n, 110}]] (* Harvey P. Dale, Feb 06 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Aug 20 2005
STATUS
approved