A083897 Number of divisors of n with largest digit <= 2 (base 10).

1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 2, 3, 1, 2, 1, 2, 1, 2, 1, 4, 2, 4, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 1, 4, 1, 3, 1, 4, 1, 2, 1, 3, 1, 3, 1, 2, 1, 2, 2, 2, 1, 2, 1, 5, 1, 2, 2, 2, 1, 4, 1, 2, 1, 3, 1, 3, 1, 2, 1, 2, 2, 2, 1, 4, 1, 2, 1, 4, 1, 2, 1, 4, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 2, 5, 2, 3, 1, 2, 2

Offset

1,2

Links

Table of n, a(n) for n=1..105.

Formula

a(n) = A083888(n) + A083889(n) = A083898(n) - A083890(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007089(k) = 2.09476944442950059256... . - Amiram Eldar, Jan 04 2024

Mathematica

Table[Count[Divisors[n], _?(Max[IntegerDigits[#]]<3&)], {n, 110}] (* Harvey P. Dale, May 24 2019 *)

Crossrefs

Cf. A054055, A000005, A083888, A083889, A083898, A083890, A007089.

Sequence in context: A239061 A309025 A247599 * A368212 A025823 A025821

Adjacent sequences: A083894 A083895 A083896 * A083898 A083899 A083900

Keyword

nonn,base

Author

Reinhard Zumkeller, May 08 2003

Status

approved