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Search: id:A007613
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| A007613 |
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(8^n + 2(-1)^n )/3.
(Formerly M2129)
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+0
4
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| 1, 2, 22, 170, 1366, 10922, 87382, 699050, 5592406, 44739242, 357913942, 2863311530, 22906492246, 183251937962, 1466015503702, 11728124029610, 93824992236886, 750599937895082, 6004799503160662, 48038396025285290
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Equals row sums of triangle A139459(n+1). Example: 170 = (1 + 84 + 84 + 1). Triangle A139459 = the ConvOffsStoT transform of the dodecahedral numbers, A006560. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 22 2008
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
D. S. Clark, Proof without words, Math. Mag., 63 (1990), 29.
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FORMULA
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a(n)=A078008(3n) - Paul Barry (pbarry(AT)wit.ie), Nov 29 2003
a(n)=(A082311(n)+(-1)^n)/2=(A001045(3n+1)+(-1)^n)/2. - Paul Barry (pbarry(AT)wit.ie), Mar 24 2004
a(n)=sum{k=0..n, binomial(3n, 3k)}; - Paul Barry (pbarry(AT)wit.ie), Jan 13 2005
a(n)=8a(n-1)+6*(-1)^n. - Paul Curtz (bpcrtz(AT)free.fr), Nov 19 2007
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CROSSREFS
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Cf. A006560, A139459.
Adjacent sequences: A007610 A007611 A007612 this_sequence A007614 A007615 A007616
Sequence in context: A123960 A091169 A000184 this_sequence A043037 A058441 A037567
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Robert G. Wilson v (rgwv(AT)rgwv.com)
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