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Search: id:A130763
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| A130763 |
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Natural numbers such that d(n)!+ 1 is a square, where d(n) is the number of divisors of n, A000005. |
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+0
1
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| 6, 8, 10, 14, 15, 16, 21, 22, 26, 27, 33, 34, 35, 38, 39, 46, 51, 55, 57, 58, 62, 64, 65, 69, 74, 77, 81, 82, 85, 86, 87, 91, 93, 94, 95, 106, 111, 115, 118, 119, 122, 123, 125, 129, 133, 134, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 177, 178, 183, 185, 187
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is generally assumed that the diophantic equation n!+1=m^2 can only be solved for n = 4,5,7. - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 21 2007
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MATHEMATICA
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Select[Range[1000], IntegerQ[Sqrt[Length[Divisors[ # ]]! + 1]] &] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 21 2007
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CROSSREFS
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Cf. A000005.
Sequence in context: A153032 A086822 A048943 this_sequence A120497 A036436 A036455
Adjacent sequences: A130760 A130761 A130762 this_sequence A130764 A130765 A130766
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KEYWORD
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nonn
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Aug 17 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 21 2007
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