A188642 - OEIS

A188642

Characteristic function of numbers that are divisible by the product of their digits.

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0

(list; graph; refs; listen; history; text; internal format)

OFFSET

COMMENTS

a(A007602(n)) = a(A038186(n)) = 1; a(A188643(n)) = 0.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000 (corrected by Georg Fischer, Jan 20 2019)

Index entries for characteristic functions

MAPLE

isA007602 := proc(n) if A007954(n) = 0 then false; else `if`(n mod A007954(n) = 0, true, false) ; end if; end proc:

A188642 := proc(n) if isA007602(n) then 1; else 0 ; end if ; end proc:

seq(A188642(n), n=0..30) ; # R. J. Mathar, Apr 08 2011

MATHEMATICA

dpdQ[n_]:=Module[{idn=IntegerDigits[n]}, FreeQ[idn, 0]&&Mod[n, Times@@idn]==0]; Table[ If[dpdQ[n], 1, 0], {n, 0, 120}] (* Harvey P. Dale, May 06 2023 *)

PROG

(Haskell)

a188642 n

| a168046 n == 1 = 1 - signum (n `mod` a007954 n)

| otherwise = 0

a188642_list = map a188642 [0..]

CROSSREFS

Cf. A007954, A168046, A188641.

Sequence in context: A168182 A204447 A368905 * A168046 A168184 A013595

Adjacent sequences: A188639 A188640 A188641 * A188643 A188644 A188645

KEYWORD

nonn,base

AUTHOR

Reinhard Zumkeller, Apr 07 2011

STATUS

approved