A001104 - OEIS

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A001104

Numbers n such that n / product of digits of n is a square.

1, 2, 3, 4, 5, 6, 7, 8, 9, 135, 144, 384, 1575, 1715, 6144, 6912, 11664, 14112, 16224, 18816, 23328, 26136, 31212, 41616, 82944, 83232, 93312, 131424, 131712, 186624, 248832, 371112, 1168128, 2214144, 2239488, 2333772, 3321216, 3881472, 6642432

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

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..39.

MATHEMATICA

Select[Range[665*10^4], IntegerQ[Sqrt[#/Times@@IntegerDigits[#]]]&]// Quiet (* Harvey P. Dale, May 09 2019 *)

PROG

(PARI) isok(n) = {digs = digits(n); q = prod(i=1, #digs, digs[i]); (q != 0) && (n % q == 0) && issquare(n/q); } \\ Michel Marcus, Sep 04 2013

CROSSREFS

Sequence in context: A059405 A191872 A280355 * A151544 A032561 A342157

Adjacent sequences: A001101 A001102 A001103 * A001105 A001106 A001107

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Bill Moran (moran1(AT)llnl.gov)

STATUS

approved