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A062371
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Numbers the product of whose nonzero digits is a perfect square.
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2
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1, 4, 9, 10, 11, 14, 19, 22, 28, 33, 40, 41, 44, 49, 55, 66, 77, 82, 88, 90, 91, 94, 99, 100, 101, 104, 109, 110, 111, 114, 119, 122, 128, 133, 140, 141, 144, 149, 155, 166, 177, 182, 188, 190, 191, 194, 199, 202, 208, 212, 218, 220, 221, 224, 229, 236, 242, 248
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refs;
listen;
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internal format)
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OFFSET
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0,2
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LINKS
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EXAMPLE
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128 is a member as 1*2*8 = 16 is a square. 140 is also a member as 1*4 = 4.
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PROG
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(PARI) ProdNzD(x)= { p=1; while (x>9, d=x-10*(x\10); if (d, p*=d); x\=10); return(p*x) } { n=-1; for (m=1, 10^9, if (issquare(ProdNzD(m)), write("b062371.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 06 2009
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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Corrected and extended by Larry Reeves (larryr(AT)acm.org), Jul 06 2001
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STATUS
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approved
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