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A152891
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a=b=0;b(n)=b+n+a;a(n)=a+n+b.
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4
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0, 2, 9, 29, 83, 226, 602, 1588, 4171, 10935, 28645, 75012, 196404, 514214, 1346253, 3524561, 9227447, 24157798, 63245966, 165580120, 433494415, 1134903147, 2971215049, 7778742024, 20365011048, 53316291146, 139583862417
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Partial sums of A035508. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 15 2008]
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LINKS
| Guo-Niu Han, Enumeration of Standard Puzzles
Index to sequences with linear recurrences with constant coefficients, signature (5,-8,5,-1).
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FORMULA
| G.f.: x^2(2-x)/((1-3x+x^2)(1-x)^2). a(n)=A001906(n+1)-A001906(n)-n-1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 15 2008]
a(n)=F(2n+1)-n-1, where F(m)=A000045(m) are the Fibonacci numbers (F(0)=0, F(1)=1). [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 01 2009]
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MAPLE
| with(combinat): seq(fibonacci(2*n+1)-n-1, n = 1 .. 27); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 01 2009]
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MATHEMATICA
| lst={}; a=b=0; Do[b+=n+a; a+=n+b; AppendTo[lst, a], {n, 0, 2*4!}]; lst
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CROSSREFS
| Cf. A000045 [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 01 2009]
Sequence in context: A090208 A123058 A062452 * A181545 A069006 A183383
Adjacent sequences: A152888 A152889 A152890 * A152892 A152893 A152894
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KEYWORD
| nonn
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AUTHOR
| Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 14 2008
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