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A081989
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Product of digits + 1 is a square greater than 1.
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1
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3, 8, 13, 18, 24, 31, 35, 38, 42, 46, 53, 57, 64, 68, 75, 79, 81, 83, 86, 97, 113, 118, 124, 131, 135, 138, 142, 146, 153, 157, 164, 168, 175, 179, 181, 183, 186, 197, 214, 222, 226, 234, 238, 241, 243, 246, 258, 262, 264, 283, 285
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OFFSET
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0,1
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COMMENTS
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Sequence is infinite.
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LINKS
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EXAMPLE
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135 belongs to this sequence as 1*3*5 + 1 = 16 is a square.
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MATHEMATICA
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pdsQ[n_]:=FreeQ[IntegerDigits[n], 0]&&IntegerQ[ Sqrt[ 1+Times@@ IntegerDigits[ n]]]; Select[Range[300], pdsQ] (* Harvey P. Dale, Jul 13 2021 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003
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STATUS
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approved
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