A083900 Number of divisors of n with largest digit <= 5 (base 10).

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

Offset: 1

Author

Reinhard Zumkeller, May 08 2003

Keywords

• nonn
• base

Crossrefs

Cf. A054055, A000005, A007092, A083892, A083893, A083899, A083901.

Programs

Mathematica

Table[Count[Divisors[n],?(Max[IntegerDigits[#]]<6&)],{n,110}] (* _Harvey P. Dale, Feb 02 2015 *)

Formula

a(n) = A083899(n) + A083892(n) = A083901(n) - A083893(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007092(k) = 5.25448032967060504709... . - Amiram Eldar, Jan 04 2024