A083902 Number of divisors of n with the largest digit of the divisor <= 7 (base 10).

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

Offset

1,2

Links

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

Formula

a(n) = A083901(n) + A083894(n) = A083903(n) - A083895(n).

Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007094(k) = 11.2915816168324913817... . - Amiram Eldar, Jan 04 2024

Mathematica

Table[Count[Divisors[n], _?(Max[IntegerDigits[#]]<8&)], {n, 110}] (* Harvey P. Dale, Nov 01 2022 *)

Crossrefs

Cf. A054055, A000005, A007094, A083894, A083895, A083901, A083903.

Sequence in context: A366742 A141829 A111336 * A205562 A217984 A196437

Adjacent sequences: A083899 A083900 A083901 * A083903 A083904 A083905

Keyword

nonn,base

Author

Reinhard Zumkeller, May 08 2003

Extensions

Definition clarified by Harvey P. Dale, Nov 01 2022

Status

approved