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Search: id:A099202
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| 1, 1, 4, 16, 256, 4096, 262144, 16777216, 4294967296, 1099511627776, 1125899906842624, 1152921504606846976, 4722366482869645213696, 19342813113834066795298816, 316912650057057350374175801344
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Hankel transform of A168490. Linked to elliptic curve y^2=1-12x+44x^2-48x^3 through g.f. of A168490. [From Paul Barry (pbarry(AT)wit.ie), Nov 27 2009]
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FORMULA
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a(n)=A016116(n)*A006125(n)
a(n)=16a(n-2)^2/a(n-4). - Michael Somos Sep 16 2005
a(n)=4^floor(n^2/4)=4^A002620(n). [From Paul Barry (pbarry(AT)wit.ie), Nov 27 2009]
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PROGRAM
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(PARI) a(n)=2^(n^2\2)
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CROSSREFS
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Sequence in context: A000513 A088027 A113905 this_sequence A139288 A152921 A152153
Adjacent sequences: A099199 A099200 A099201 this_sequence A099203 A099204 A099205
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KEYWORD
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easy,nonn,new
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Oct 04 2004
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