A083901 Number of divisors of n with largest digit <= 6 (base 10).

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

Offset

1,2

Links

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

Formula

a(n) = A083900(n) + A083893(n) = A083902(n) - A083894(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007093(k) = 7.32338572355014919630... . - Amiram Eldar, Jan 04 2024

Mathematica

a[n_] := DivisorSum[n, 1 &, Max[IntegerDigits[#]] <= 6 &]; Array[a, 100] (* Amiram Eldar, Jan 04 2024 *)

Crossrefs

Cf. A054055, A000005, A007093, A083893, A083894, A083900, A083902.

Sequence in context: A242213 A035213 A340224 * A274517 A355583 A368543

Adjacent sequences: A083898 A083899 A083900 * A083902 A083903 A083904

Keyword

nonn,base

Author

Reinhard Zumkeller, May 08 2003

Status

approved