A083898 Number of divisors of n with largest digit <= 3 (base 10).

1, 2, 2, 2, 1, 3, 1, 2, 2, 3, 2, 4, 2, 2, 2, 2, 1, 3, 1, 4, 3, 4, 2, 4, 1, 3, 2, 2, 1, 5, 2, 3, 4, 2, 1, 4, 1, 2, 3, 4, 1, 4, 1, 4, 2, 3, 1, 4, 1, 3, 2, 3, 1, 3, 2, 2, 2, 2, 1, 7, 1, 3, 3, 3, 2, 6, 1, 2, 3, 3, 1, 4, 1, 2, 2, 2, 2, 4, 1, 4, 2, 2, 1, 5, 1, 2, 2, 4, 1, 5, 2, 3, 3, 2, 1, 5, 1, 2, 4, 5, 2, 4, 2, 3, 3

Offset

1,2

Links

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

Formula

a(n) = A083897(n) + A083890(n) = A083899(n) - A083891(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007090(k) = 2.93694402167748963905... . - Amiram Eldar, Jan 04 2024

Mathematica

Table[Count[Divisors[n], _?(Total[Most[Drop[DigitCount[#], 3]]]==0&)], {n, 120}] (* Harvey P. Dale, Dec 21 2018 *)

Crossrefs

Cf. A054055, A000005, A007090, A083890, A083891, A083897, A083899.

Sequence in context: A106253 A078720 A270488 * A392758 A078314 A330894

Adjacent sequences: A083895 A083896 A083897 * A083899 A083900 A083901

Keyword

nonn,base

Author

Reinhard Zumkeller, May 08 2003

Status

approved