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A139818
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Squares of Jacobsthal numbers.
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3
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0, 1, 1, 9, 25, 121, 441, 1849, 7225, 29241, 116281, 466489, 1863225, 7458361, 29822521, 119311929, 477204025, 1908903481, 7635439161, 30542106169, 122167725625, 488672300601, 1954686406201, 7818751217209, 31274993684025
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index to sequences with linear recurrences with constant coefficents, signature (3,6,-8). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 12 2009]
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FORMULA
| a(n)=3a(n-1)+6a(n-2)-8a(n-3).
a(n)=1/9-(2/9)*(-2)^n+(1/9)*4^n, with n>=0 - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 12 2008
a(n) = (A001045(n))^2. G.f.: x*(1-2*x)/((1-x)*(1+2*x)*(1-4*x)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 12 2009]
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PROG
| (MAGMA) [1/9-(2/9)*(-2)^n+(1/9)*4^n: n in [0..35]]; // Vincenzo Librandi, Aug 09 2011
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CROSSREFS
| Cf. A001019, First differences give (apart from signs) A083086.
Sequence in context: A084058 A108570 A092769 * A146365 A146373 A084605
Adjacent sequences: A139815 A139816 A139817 * A139819 A139820 A139821
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KEYWORD
| nonn,easy
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), May 17 2008
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 12 2009
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