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Search: id:A060182
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| A060182 |
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a(0) = 1, a(1) = 5, a(2) = 13; a(n) = 2*a(n-1) + 2, n > 2. |
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+0
2
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| 1, 5, 13, 28, 58, 118, 238, 478, 958, 1918, 3838, 7678, 15358, 30718, 61438, 122878, 245758, 491518, 983038, 1966078, 3932158, 7864318, 15728638, 31457278, 62914558, 125829118, 251658238, 503316478, 1006632958, 2013265918
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Sometimes confused with A002717.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=0,...,200
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FORMULA
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a_n = 3((a_n-1)-(a_n-2)+(a_n-3)-...((-1)^(n+1))a_0)+1; a_n = (2^(n-3))a_3 + (2^(n-2))-2 for n > 3.
G.f.: -(1+x)*(x^2-x-1)/((-1+x)*(-1+2*x)). a(n)=15*2^(n-2)-2, n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 15 2009]
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PROGRAM
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(PARI) { a=-1; for (n=0, 200, a=2*a + 2; if (n<3, a++); write("b060182.txt", n, " ", a); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 02 2009]
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CROSSREFS
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Sequence in context: A027962 A023537 A023653 this_sequence A147066 A133204 A152658
Adjacent sequences: A060179 A060180 A060181 this_sequence A060183 A060184 A060185
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KEYWORD
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nonn,easy
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AUTHOR
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Brian Wallace (wallacebrianedward(AT)yahoo.co.uk), Mar 19 2001
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EXTENSIONS
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Simpler formula and more terms from Larry Reeves (larryr(AT)acm.org), Mar 30 2001
Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of Philippe LALLOUET (philip.lallouet(AT)wanadoo.fr), Sep 16 2007
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