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Search: id:A131183
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| A131183 |
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a(n) = a(n-1)+a(n-2) if n == 3 mod 4; a(n) = a(n-1)-a(n-2) if n == 0 mod 4; a(n) = a(n-1)*a(n-2) if n == 1 mod 4; and a(n) = a(n-1)/a(n-2) if n == 2 mod 4; with a(1))=a(2)=1 |
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+0
1
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| 1, 1, 2, 1, 2, 2, 4, 2, 8, 4, 12, 8, 96, 12, 108, 96, 10368, 108, 10476, 10368, 108615168, 10476, 108625644, 108615168, 11798392572168192, 108625644, 11798392680793836, 11798392572168192, 139202068568601556987554268864512
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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If S(n)=a(4n-1) (i.e. term "+"), R(n)=a(4n) (i.e. "-"), P(n)=a(4n+1), D(n)=a(4n+2) then D(n)=S(n), P(n)= S(n+1)-S(n), R(n+1)=P(n)=S(n+1)-S(n). - Jose Ramon Real (joseramonreal(AT)yahoo.es), Nov 10 2007
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EXAMPLE
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a(3)=a(2)+a(1)=1+1=2
a(4)=a(3)-a(2)=2-1=1
a(5)=a(4)*a(3)=1*2=2
a(6)=a(5)/a(4)=2/1=2
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MAPLE
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A131183 := proc(n) option remember ; if n <= 2 then 1 ; elif n mod 4 = 3 then A131183(n-1)+A131183(n-2) ; elif n mod 4 = 0 then A131183(n-1)-A131183(n-2) ; elif n mod 4 = 1 then A131183(n-1)*A131183(n-2) ; else A131183(n-1)/A131183(n-2) ; fi ; end: seq(A131183(n), n=1..35) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 28 2007
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CROSSREFS
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Sequence in context: A054541 A102722 A020475 this_sequence A133770 A163373 A117193
Adjacent sequences: A131180 A131181 A131182 this_sequence A131184 A131185 A131186
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KEYWORD
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easy,nonn
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AUTHOR
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Jose Ramon Real (joseramonreal(AT)yahoo.es), Oct 22 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 28 2007
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