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A061867 Squares whose product of digits is also a square (allowing zeros). 2
0, 1, 4, 9, 49, 100, 144, 289, 400, 441, 900, 1024, 1089, 1444, 1600, 2025, 2209, 2304, 2401, 2500, 2601, 2704, 2809, 3025, 3600, 4096, 4900, 5041, 6084, 6400, 7056, 7744, 8100, 9025, 9409, 9604, 9801, 10000, 10201, 10404, 10609, 10816, 11025, 11236 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
REFERENCES
Felice Russo, A set of new Smarandache Functions, Sequences and conjectures in number theory, pp-64, American Research Press, Lupton USA.
Amarnath Murthy, Exploring some new ideas on Smarandache Type Sets, Functions and sequences, Vol. 11, No. 1-2-3, Spring 2000.
Amarnath Murthy, On the infinitude of Smarandache multiplicative square sequence, (to be published in Smarandache Notions Journal).
LINKS
FORMULA
a(n) ~ n^2. - Charles R Greathouse IV, Sep 19 2012
MATHEMATICA
Select[Range[0, 200]^2, IntegerQ[Sqrt[Times@@IntegerDigits[#]]]&] (* Harvey P. Dale, Oct 03 2014 *)
PROG
(PARI) isok(n) = {if (! issquare(n), return (0)); digs = digits(n, 10); issquare(prod(i=1, #digs, digs[i])); } \\ Michel Marcus, Aug 02 2013
CROSSREFS
Sequence A053059 removes the numbers with zeros.
Sequence in context: A055812 A368337 A268099 * A019544 A053059 A006716
KEYWORD
base,easy,nonn
AUTHOR
Larry Reeves (larryr(AT)acm.org), May 11 2001
STATUS
approved

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Last modified May 30 06:43 EDT 2024. Contains 372958 sequences. (Running on oeis4.)