A083903 Number of divisors of n with largest digit <= 8 (base 10).

1, 2, 2, 3, 2, 4, 2, 4, 2, 4, 2, 6, 2, 4, 4, 5, 2, 5, 1, 6, 4, 4, 2, 8, 3, 4, 3, 6, 1, 8, 2, 6, 4, 4, 4, 8, 2, 3, 3, 8, 2, 8, 2, 6, 5, 4, 2, 10, 2, 6, 4, 6, 2, 7, 4, 8, 3, 3, 1, 12, 2, 4, 5, 7, 4, 8, 2, 6, 3, 8, 2, 11, 2, 4, 6, 5, 4, 7, 1, 10, 4, 4, 2, 12, 4, 4, 3, 8, 1, 10, 3, 5, 3, 3, 2, 11, 1, 4, 4, 9, 2, 8

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

a(n) = A083902(n) + A083895(n) = A000005(n) - A083896(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007095(k) = 22.920676... (A082838). - Amiram Eldar, Jan 04 2024

Mathematica

Table[Length[DeleteCases[Divisors[n], _?(Max[IntegerDigits[#]]==9&)]], {n, 110}] (* Harvey P. Dale, Nov 21 2015 *)

Crossrefs

Cf. A054055, A000005, A007095, A082838, A083895, A083896, A083902.

Sequence in context: A343650 A327391 A365207 * A327536 A341946 A339915

Adjacent sequences: A083900 A083901 A083902 * A083904 A083905 A083906

Keyword

nonn,base

Author

Reinhard Zumkeller, May 08 2003

Status

approved