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Search: id:A024088
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| 0, 7, 63, 511, 4095, 32767, 262143, 2097151, 16777215, 134217727, 1073741823, 8589934591, 68719476735, 549755813887, 4398046511103, 35184372088831, 281474976710655, 2251799813685247, 18014398509481983
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OFFSET
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0,2
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COMMENT
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Numbers whose base 8 or octal representation is 777777.......7. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 03 2007
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FORMULA
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G.f.: 1/(1-8*x)-1/(1-x). E.g.f.: e^(8*x)-e^x. [From Mohammad K. Azarian (azarian(AT)evansville.edu), Jan 14 2009]
a(n) = A000225(n)*A001576(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 15 2009]
a(n)=8*a(n-1)+7 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 30 2009]
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EXAMPLE
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For n=2, a(2)=8*0+7=7; n=3, a(3)=8*7+7=63; n=4, a(4)=8*63+7=511 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 30 2009]
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PROGRAM
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(Other) sage: [gaussian_binomial(3*n, 1, 2) for n in xrange(0, 19)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 28 2009]
(Other) sage: [stirling_number2(3*n+1, 2) for n in xrange(0, 19)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 26 2009]
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CROSSREFS
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Sequence in context: A165759 A166153 A123009 this_sequence A155132 A015684 A051579
Adjacent sequences: A024085 A024086 A024087 this_sequence A024089 A024090 A024091
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KEYWORD
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nonn,new
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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