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A010685
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Period 2: repeat [1,4].
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16
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1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(n) = A160700(A000302(n)). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 10 2009]
4^n mod 5. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 26 2009]
Continued fraction of (1+sqrt 2)/2. - R. J. Mathar, Nov 21 2011
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FORMULA
| a(2n)=1, a(2n+1)=4.
G.f.:(1+4x)/((1-x)(1+x)); E.g.f.:(5exp(x)-3exp(-x))/2; a(n)=(5-3(-1)^n)/2; a(n)=4^((1-(-1)^n)/2)=2^(1-(-1)^n)=2/(2^((-1)^n)); a(n)=4^(ceiling(n/2)-floor(n/2)). - Paul Barry (pbarry(AT)wit.ie), Jun 03 2003
a(n)=gcd((n-1)^2, (n+1)^2) - Paul Barry (pbarry(AT)wit.ie), Sep 16 2004
a(n) = 4*(n mod 2)+(n+1) mod 2 - Paolo P. Lava (paoloplava(AT)gmail.com), Oct 20 2006
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MAPLE
| [seq (modp((3*n+1), 6), n=0..80)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 30 2006
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PROG
| (Other) sage: [power_mod(4, n, 5)for n in xrange(0, 81)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 26 2009]
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CROSSREFS
| Sequence in context: A144865 A096622 A080905 * A174571 A099301 A050347
Adjacent sequences: A010682 A010683 A010684 * A010686 A010687 A010688
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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