A038769 Number of digits of n which are divisors of n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 0, 2, 1, 1, 0, 1, 0, 1, 1, 1, 2, 0, 1, 2, 0, 0, 1, 1, 1, 1, 0, 2, 1, 0, 0, 2, 0, 1, 1, 1, 0, 0, 2, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 2, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 2, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 2, 1, 2, 2, 1, 2, 2

Offset

1,11

Comments

a(A038772(n)) = 0; a(A038770(n)) > 0.

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Example

a(35)=1 because 5 is a divisor of 35 but 3 is not.

Maple

f:= proc(n) local L; L:= convert(n, base, 10);
  nops(select(t -> t > 0 and n mod t = 0, L))
end proc:
map(f, [$1..1000]); # Robert Israel, Jul 04 2016

Mathematica

Array[Count[Position[Most@ DigitCount@ #, _?(# > 0 &)][[All, 1]], k_ /; Mod[#, k] == 0] &, 105] (* Michael De Vlieger, Dec 23 2019 *)
Table[Count[n/Select[IntegerDigits[n], #>0&], _?IntegerQ], {n, 110}] (* Harvey P. Dale, Mar 04 2023 *)

Prog

(Haskell)
import Data.Char (digitToInt)
a038769 n = length $ filter (== 0)
            $ map ((mod n) . digitToInt) $ filter (> '0') $ show n
-- Reinhard Zumkeller, Jun 19 2011
(Magma) [#[c:c in Intseq(k) |not IsZero(c) and k mod c eq 0]:k in [1..105]]; // Marius A. Burtea, Dec 23 2019

Crossrefs

Cf. A034709, A034837, A038770, A038772.

Sequence in context: A072550 A037810 A335211 * A327818 A255481 A241418

Adjacent sequences: A038766 A038767 A038768 * A038770 A038771 A038772

Keyword

nonn,base,easy

Author

Henry Bottomley, May 04 2000

Status

approved