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A166743
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a(n) = (2^p - p^2 - 1)/6 where p = prime(n).
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1
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1, 13, 321, 1337, 21797, 87321, 1398013, 89478345, 357913781, 22906492017, 366503875645, 1466015503393, 23456248058853, 1501199875789697, 96076792050570001, 384307168202281705, 24595658764946068073
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OFFSET
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3,2
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LINKS
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Harvey P. Dale, Table of n, a(n) for n = 3..468
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FORMULA
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a(n) = (A034785(n) - A066872(n))/6. - R. J. Mathar, Oct 25 2009
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MAPLE
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A166743 := proc(n) p := ithprime(n) ; (2^p-p^2-1)/6 ; end: seq(A166743(n), n=3..20) ; # R. J. Mathar, Oct 25 2009
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MATHEMATICA
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Table[(2^p-p^2-1)/6, {p, Prime[Range[3, 20]]}] (* Harvey P. Dale, May 16 2020 *)
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CROSSREFS
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Cf. A034785, A066872.
Sequence in context: A305143 A132485 A297437 * A212733 A183803 A253458
Adjacent sequences: A166740 A166741 A166742 * A166744 A166745 A166746
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KEYWORD
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nonn
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AUTHOR
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Tanin (Mirza Sabbir Hossain Beg) (mirzasabbirhossainbeg(AT)yahoo.com), Oct 21 2009
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EXTENSIONS
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Missing exponentiation signs inserted in the definition by R. J. Mathar, Oct 25 2009
Corrected by D. S. McNeil, Aug 20 2010
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STATUS
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approved
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