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A094015
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Expansion of (1+4x)/(1-8x^2).
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6
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1, 4, 8, 32, 64, 256, 512, 2048, 4096, 16384, 32768, 131072, 262144, 1048576, 2097152, 8388608, 16777216, 67108864, 134217728, 536870912, 1073741824, 4294967296, 8589934592, 34359738368, 68719476736, 274877906944
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| a(n)=2^(3n/2)(1+sqrt(2)+(1-sqrt(2))(-1)^n)/2
a(n)=(1/4)(3+(-1)^n)8^floor((n+1)/2) - Paul Barry (pbarry(AT)wit.ie), Jul 14 2004
a(n)=(1+sqrt(2))(2sqrt(2))^n/2+(1-sqrt(2))(-2sqrt(2))^n/2. Third binomial transform is A002315 (NSW numbers). - Paul Barry (pbarry(AT)wit.ie), Jul 17 2004
a(n)=2^A007494(n). - Paul Barry (pbarry(AT)wit.ie), Aug 18 2007
Row sums of triangle A135838 - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 01 2007
a(n)=A016116(n+1)*A000079(n). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 08 2009]
a(n+3) = a(n+2)*a(n+1)/a(n). [Reinhard Zumkeller, Mar 04 2011]
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MAPLE
| a:=n->mul(3-(-1)^j, j=1..n):seq(a(n), n=0..25); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 13 2008]
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CROSSREFS
| Cf. A094014.
Cf. A135838.
Sequence in context: A173617 A034041 A050442 * A094867 A149093 A149094
Adjacent sequences: A094012 A094013 A094014 * A094016 A094017 A094018
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Apr 21 2004
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