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 A007602 Numbers that are divisible by the product of their digits. (Formerly M0482) 49
 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, 24, 36, 111, 112, 115, 128, 132, 135, 144, 175, 212, 216, 224, 312, 315, 384, 432, 612, 624, 672, 735, 816, 1111, 1112, 1113, 1115, 1116, 1131, 1176, 1184, 1197, 1212, 1296, 1311, 1332, 1344, 1416, 1575, 1715, 2112, 2144 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS These are called Zuckerman numbers to base 10. [So-named by J. J. Tattersall, after Herbert S. Zuckerman. - Charles R Greathouse IV, Jun 06 2017] - Howard Berman (howard_berman(AT)hotmail.com), Nov 09 2008 This sequence is a subsequence of A180484; the first member of A180484 that is not a member of A007602 is 1114. - D. S. McNeil, Sep 09 2010 Complement of A188643; A188642(a(n)) = 1; A038186 is a subsequence; A168046(a(n)) = 1: subsequence of A052382. - Reinhard Zumkeller, Apr 07 2011 The terms of n digits in the sequence, for n from 1 to 14, are 9, 5, 20, 40, 117, 285, 747, 1951, 5229, 13493, 35009, 91792, 239791, 628412, 1643144, 4314987. Empirically, the counts seem to grow as 0.858*2.62326^n. - Giovanni Resta, Jun 25 2017 De Koninck and Luca showed that the number of Zuckerman numbers below x is at least x^0.122 but at most x^0.863. - Tomohiro Yamada, Nov 17 2017 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Reinhard Zumkeller and Zak Seidov, Table of n, a(n) for n = 1..10000 Jean-Marie De Koninck and Florian Luca, Positive integers divisible by the product of their nonzero digits, Port. Math. 64 (2007) 75-85. (This proof for upper bounds contains an error. See the paper below) Jean-Marie De Koninck and Florian Luca, Corrigendum to "Positive integers divisible by the product of their nonzero digits", Portugaliae Math. 64 (2007), 1: 75-85, Port. Math. 74 (2017), 169-170. James J. Tattersall, Elementary Number Theory in Nine Chapters (2005), 2nd Edition. p. 86 (see problems 44-45). MAPLE filter:= proc(n) local p; p:= convert(convert(n, base, 10), `*`); p <> 0 and n mod p = 0 end proc; select(filter, [\$1..10000]); # Robert Israel, Aug 24 2014 MATHEMATICA zuckerQ[n_] := Module[{d = IntegerDigits[n], prod}, prod = Times @@ d; prod > 0 && Mod[n, prod] == 0]; Select[Range, zuckerQ] (* Alonso del Arte, Aug 04 2004 *) PROG (Haskell) import Data.List (elemIndices) a007602 n = a007602_list !! (n-1) a007602_list = map succ \$ elemIndices 1 \$ map a188642 [1..] -- Reinhard Zumkeller, Apr 07 2011 (MAGMA) [ n: n in [1..2144] | not IsZero(&*Intseq(n)) and IsZero(n mod &*Intseq(n)) ];  // Bruno Berselli, May 28 2011 (Python) from operator import mul from functools import reduce A007602 = [n for n in range(1, 10**5) if not (str(n).count('0') or n % reduce(mul, (int(d) for d in str(n))))] # Chai Wah Wu, Aug 25 2014 (PARI) for(n=1, 10^5, d=digits(n); p=prod(i=1, #d, d[i]); if(p&&n%p==0, print1(n, ", "))) \\ Derek Orr, Aug 25 2014 CROSSREFS Cf. A002796, A034709, A034838, A001103, A005349. Cf. A286590 (for factorial-base analog). Cf. A288069 (quotients). Subsequence of A055471. Sequence in context: A308472 A064700 A180484 * A337941 A167620 A169935 Adjacent sequences:  A007599 A007600 A007601 * A007603 A007604 A007605 KEYWORD nonn,base,easy AUTHOR STATUS approved

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Last modified October 23 03:59 EDT 2020. Contains 337962 sequences. (Running on oeis4.)