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A229544 Numbers n such that n*product_of_digits(n) is a nonzero cube. 0
1, 8, 243, 784, 7776, 9826, 13122, 24389, 26244, 39366, 47628, 55566, 59895, 71442, 82944, 122825, 124416, 226981, 263424, 275625, 316368, 323433, 333396, 588245, 663255, 774144, 843648, 1339893, 1492992, 1613472, 2341344, 3816336, 3981312, 8719893, 8992364, 9393931, 9927988, 11212884, 11239424, 14823774 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..40.

EXAMPLE

7776*(7*7*7*6) = 1600030008 = 252^3. Thus, 7776 is a member of this sequence.

PROG

(Python)

def DP(n):

..p = 1

..for i in str(n):

....p *= int(i)

..return p

def a(n):

..k = 0

..while k < n:

....if k**3 == n*DP(n):

......return n

....if k**3 > n*DP(n):

......return 0

....k += 1

n = 1

while n < 10**6:

..if a(n):

....print(n, end=', ')

..n += 1

# Simplified by Derek Orr, Mar 22 2015

(PARI) for(n=1, 10^7, d=digits(n); p=prod(i=1, #d, d[i]); if(p&&ispower(n*p, 3), print1(n, ", "))) \\ Derek Orr, Mar 22 2015

CROSSREFS

Cf. A066565, A098736.

Sequence in context: A272236 A272239 A227319 * A115613 A209540 A085524

Adjacent sequences:  A229541 A229542 A229543 * A229545 A229546 A229547

KEYWORD

nonn,base

AUTHOR

Derek Orr, Sep 25 2013

EXTENSIONS

Corrected and extended by Derek Orr, Mar 22 2015

STATUS

approved

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Last modified October 15 21:38 EDT 2021. Contains 348034 sequences. (Running on oeis4.)