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A105385
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Expansion of (1-x^2)/(1-x^5).
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1
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1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1, 0, -1, 0, 0, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| Binomial transform is A103311(n+1). Consecutive pair sums of A105384. Periodic {1,0,-1,0,0}.
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FORMULA
| G.f.: (1+x)/(1+x+x^2+x^3+x^4); a(n)=sqrt(1/5-2sqrt(5)/25)cos(4*pi*n/5+pi/10)+sqrt(5)sin(4*pi*n/5+pi/10)/5+ sqrt(2sqrt(5)/25+1/5)cos(2*pi*n/5+3*pi/10)+sqrt(5)sin(2*pi*n/5+3*pi/10)/5
a(n)=-(1/5)*{[n mod 5]+[(n+2) mod 5]-[(n+3) mod 5]-[(n+4) mod 5]}, with n>=0. - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 01 2007
a(n)=A092202(n+1). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 28 2008]
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CROSSREFS
| Cf. A198517 (unsigned version).
Sequence in context: A127829 A127831 A164364 * A090626 A129569 A030658
Adjacent sequences: A105382 A105383 A105384 * A105386 A105387 A105388
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KEYWORD
| sign,easy
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Apr 02 2005
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