|
|
A083892
|
|
Number of divisors of n with largest digit = 5 (base 10).
|
|
12
|
|
|
0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 3, 0, 0, 0, 0, 3, 1, 1, 1, 1, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 3, 0, 0, 0, 0, 1, 0, 0, 0, 0, 3, 0, 1, 0, 1, 4
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,15
|
|
LINKS
|
|
|
FORMULA
|
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A283608(k) = 1.32926350368137107677... . - Amiram Eldar, Jan 04 2024
|
|
EXAMPLE
|
n=125, 3 of the 4 divisors of 125 have largest digit =5: {5,25,125}, therefore a(125)=3.
|
|
MAPLE
|
f:= proc(n) nops(select(t -> max(convert(t, base, 10))=d, numtheory:-divisors(n))) end proc:
d:= 5:
|
|
MATHEMATICA
|
Table[Count[Divisors[n], _?(Max[IntegerDigits[#]]==5&)], {n, 110}] (* Harvey P. Dale, Aug 08 2015 *)
|
|
PROG
|
[#[d:d in Divisors(n) | Max(Intseq(d)) eq 5]: n in [1..150]]; // Marius A. Burtea, Oct 06 2019
|
|
CROSSREFS
|
Cf. A054055, A000005, A083900, A083888, A083889, A083890, A083891, A083893, A083894, A083895, A083896, A283608.
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|