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A061867
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Squares whose product of digits is also a square (allowing zeros).
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2
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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
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OFFSET
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1,3
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REFERENCES
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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).
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LINKS
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FORMULA
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MATHEMATICA
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Select[Range[0, 200]^2, IntegerQ[Sqrt[Times@@IntegerDigits[#]]]&] (* Harvey P. Dale, Oct 03 2014 *)
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PROG
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(PARI) isok(n) = {if (! issquare(n), return (0)); digs = digits(n, 10); issquare(prod(i=1, #digs, digs[i])); } \\ Michel Marcus, Aug 02 2013
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CROSSREFS
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Sequence A053059 removes the numbers with zeros.
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KEYWORD
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base,easy,nonn
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AUTHOR
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Larry Reeves (larryr(AT)acm.org), May 11 2001
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STATUS
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approved
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