cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A288069 Quotients obtained when the Zuckerman numbers are divided by the product of their digits.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 6, 3, 3, 2, 111, 56, 23, 8, 22, 9, 9, 5, 53, 18, 14, 52, 21, 4, 18, 51, 13, 8, 7, 17, 1111, 556, 371, 223, 186, 377, 28, 37, 19, 303, 12, 437, 74, 28, 59, 9, 49, 528, 67, 93, 27, 1037, 174, 22, 151, 13, 184, 29, 514, 66, 46
Offset: 1

Views

Author

Bernard Schott, Jun 05 2017

Keywords

Comments

The Zuckerman numbers (A007602) are the numbers that are divisible by the product of their digits.
Question: Is A067251 a subsequence? No, it appears in A056770 that not all integers other than multiples of 10 can be obtained as quotient, such as 15, 16, 24, 25, 26, 32, .... (see A342941).
The limit of the sequence is infinite: for any x, there is some N such that, for all n > N, a(n) > x. Proof: a Zuckerman number with d digits is at least 10^(d-1) and has a digit product at most 9^d and so has a quotient at least 10^(d-1)/9^d which goes to infinity with d. - Charles R Greathouse IV, Jun 05 2017
The repunits A002275 are a subsequence. - Peter Schorn, Apr 05 2025

Examples

			a(11) = 12/(1*2) = 6; a(13) = 24/(2*4) = 3.
		

Crossrefs

Programs

  • Maple
    f:= proc(n) local L,p;
       p:= convert(convert(n,base,10),`*`);
       if p > 0 then
         if n mod p = 0 then return n/p fi
       fi
    end proc:
    map(f, [$1..10^4]); # Robert Israel, Jun 05 2017
  • Mathematica
    Select[Table[n/Max[Times@@IntegerDigits[n],Pi/100],{n,5000}],IntegerQ] (* Harvey P. Dale, Aug 16 2021 *)

A339757 a(n) is the number of Zuckerman numbers k for which k/A007954(k) = n, where A007954(k) is the product of the decimal digits of k.

Original entry on oeis.org

9, 1, 2, 1, 1, 1, 1, 2, 3, 0, 1, 2, 3, 1, 0, 0, 1, 3, 2, 0, 1, 2, 3, 0, 0, 0, 1, 2, 2, 0
Offset: 1

Views

Author

Michel Marcus, Apr 04 2021

Keywords

Comments

The indices of 0's are A342593.

Examples

			The integers k=1 to 9 are the Zuckerman numbers that satisfy k/A007954(k)=1, so a(1)=9.
		

Crossrefs

Cf. A007954 (product of decimal digits), A007602 (Zuckerman numbers), A056770.
Cf. A288069 (Zuckerman quotients), A342593 (Zuckerman non-quotients).

A342941 Numbers not ending with 0, that are not the quotient of a Zuckerman number divided by the product of its digits.

Original entry on oeis.org

15, 16, 24, 25, 26, 32, 35, 38, 39, 42, 43, 47, 54, 55, 58, 62, 65, 71, 73, 75, 78, 85, 87, 92, 95, 99, 105, 107, 108, 115, 116, 117, 119, 123, 125, 127, 131, 135, 137, 138, 139, 141, 142, 145, 146, 147, 155, 165, 175, 176, 178, 179, 181, 185, 189, 191, 193, 195, 197, 199
Offset: 1

Views

Author

Bernard Schott, Mar 30 2021

Keywords

Comments

Zuckerman numbers (A007602) are the numbers that are divisible by the product of their digits (see link).
Multiples of 10 are never the quotient of a Zuckerman number divided by the product of its digits, but they are not present in this sequence (see A342593).

Crossrefs

Equals A342593 \ A008592.
Subsequence of A067251.

A343050 Zuckerman numbers (A007602) ordered by increasing value of k/A007954(k) where A007954(k) is the product of the decimal digits of k.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 15, 24, 384, 175, 12, 735, 128, 672, 135, 144, 1575, 11, 1296, 139968, 624, 3276, 1886976, 224, 816, 216, 432, 34992, 1197, 12768, 315, 132, 3168, 115, 6624, 8832, 2916, 1176, 1344, 3915, 739935
Offset: 1

Views

Author

Michel Marcus, Apr 03 2021

Keywords

Comments

a(n) is the Zuckerman number corresponding to A343036(n).

Examples

			As a table, sequence begins:
   1 [1, 2, 3, 4, 5, 6, 7, 8, 9]
   2 [36]
   3 [15, 24]
   4 [384]
   5 [175]
   6 [12]
   7 [735]
   8 [128, 672]
   9 [135, 144, 1575]
  10 []
  11 [11]
  12 [1296, 139968]
  13 [624, 3276, 1886976]
  14 [224]
  15 []
  16 []
  17 [816]
  18 [216, 432, 34992]
  19 [1197, 12768]
  20 []
  21 [315]
  22 [132, 3168]
  23 [115, 6624, 8832]
  24 []
  25 []
  26 []
  27 [2916]
  28 [1176, 1344]
  29 [3915, 739935]
  30 []
  ... where the 1st column is A056770 and the number of terms per rows is A339757.
		

Crossrefs

Cf. A007954 (product of decimal digits), A007602 (Zuckerman numbers), A056770.
Cf. A288069 (Zuckerman quotients), A342593 (Zuckerman non-quotients), A343036.
Cf. A339757.

Extensions

a(29)-a(45) from David A. Corneth, Apr 03 2021
Showing 1-4 of 4 results.