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Search: id:A131192
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| A131192 |
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Numbers n such that the sequence {d(n) = (n^1 + 1) (n^2 + 2) ... (n^26 + 26) / 26! : n >= 0 } takes nonintegral values. |
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1
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| 7, 11, 18, 24, 29, 37, 40, 50, 51, 62, 73, 76, 84, 89, 95, 102, 106, 115, 128, 139, 141, 150, 154, 161, 167, 172, 180, 183, 193, 194, 205, 206, 216, 219, 227, 245, 249, 258, 260, 271, 282, 284, 293, 297
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Comment from the author: initial terms were calculated by Peter J. C. Moses; see comment in A129995. Comment from Max Alekseyev: 26! = 2^23 * 3^10 * 5^6 * 7^3 * 11^2 * 13^2 * 17 * 19 * 23 There is no divisibility for 11^2 and n in {11m+7} \ {121m+117} and for 13^2 and n in {13m+11} \ {169m+63}. Therefore a(n) is nonintegral for n in the union ( {11m+7} \ {121m+117} ) U ( {13m+11} \ {169m+63}).
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MAPLE
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d:=proc(n) options operator, arrow: (product(n^j+j, j=1..26))/factorial(26) end proc: a:=proc(n) if type(d(n), integer) = false then n else end if end proc; seq(a(n), n=1..300); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 24 2007
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CROSSREFS
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Sequence in context: A094104 A020455 A048215 this_sequence A130570 A106081 A129899
Adjacent sequences: A131189 A131190 A131191 this_sequence A131193 A131194 A131195
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KEYWORD
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nonn
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AUTHOR
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Alexander R. Povolotsky (pevnev(AT)juno.com), Sep 25 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Oct 24 2007
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