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Search: id:A103454
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| 1, 3, 15, 63, 255, 1023, 4095, 16383, 65535, 262143, 1048575, 4194303, 16777215, 67108863, 268435455, 1073741823, 4294967295, 17179869183, 68719476735, 274877906943, 1099511627775, 4398046511103, 17592186044415, 70368744177663
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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A transform of 4^n under the matrix A103452.
The square of the cotangent of the arcsin of 1/(2^n). - Al Hakanson (hawkuu(AT)excite.com), Feb 23 2006
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FORMULA
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G.f.: (1-2x+4x^2)/((1-x)(1-4x)); a(n)=sum{k=0..n, A103452(n, k)4^k}; a(n)=sum{k=0..n, (2*0^(n-k)-1)*0^(k(n-k))4^k}.
a(n)=A024036(n), n>0. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 30 2008]
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CROSSREFS
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Sequence in context: A067562 A062211 A024036 this_sequence A111303 A118339 A083858
Adjacent sequences: A103451 A103452 A103453 this_sequence A103455 A103456 A103457
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Feb 06 2005
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