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A050935
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a(1)=0, a(2)=0, a(3)=1, a(n+1) = a(n) - a(n-2).
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14
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0, 0, 1, 1, 1, 0, -1, -2, -2, -1, 1, 3, 4, 3, 0, -4, -7, -7, -3, 4, 11, 14, 10, -1, -15, -25, -24, -9, 16, 40, 49, 33, -7, -56, -89, -82, -26, 63, 145, 171, 108, -37, -208, -316, -279, -71, 245, 524, 595, 350, -174, -769, -1119, -945, -176, 943, 1888, 2064, 1121, -767, -2831, -3952
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,8
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COMMENTS
| The Ze3 sums, see A180662, of triangle A108299 equal the terms of this sequence without the two leading zeros. [Johannes W. Meijer, Aug 14 2011]
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REFERENCES
| R. Palmaccio, "Average Temperatures Modeled with Complex Numbers", MATHEMATICA AND INFOMATICS QUARTERLY, pp. 9-17 of Vol. 3, No. 1, March 1993.
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
| G.f. : x^2/(1-x+x^3); a(n+2) = sum{k=0..floor(n/3), binomial(n-2*k, k)*(-1)^k)} - Paul Barry (pbarry(AT)wit.ie), Oct 20 2004
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MAPLE
| A050935 := proc(n) option remember; if n <= 1 then 0 elif n = 2 then 1 else A050935(n-1)-A050935(n-3); fi; end: seq(A050935(n), n=0..61);
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PROG
| (Haskell)
a050935 n = a050935_list !! (n-1)
a050935_list = 0 : 0 : 1 : zipWith (-) (drop 2 a050935_list) a050935_list
-- Reinhard Zumkeller, Jan 01 2012
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CROSSREFS
| When run backwards this gives a signed version of A000931.
Cf. A099529.
Apart from signs, essentially the same as A078013.
Cf. A203400 (partial sums).
Sequence in context: A090706 A176971 * A104769 A078013 A086461 A047089
Adjacent sequences: A050932 A050933 A050934 * A050936 A050937 A050938
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KEYWORD
| easy,nice,sign
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AUTHOR
| Richard J. Palmaccio (palmacr(AT)pinecrest.edu), Dec 31 1999
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EXTENSIONS
| Offset fixed by Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 01 2012
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