Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A006495
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A006495 Real part of (1+2i)^n.
(Formerly M2880)
+0
14
1, 1, -3, -11, -7, 41, 117, 29, -527, -1199, 237, 6469, 11753, -8839, -76443, -108691, 164833, 873121, 922077, -2521451, -9653287, -6699319, 34867797, 103232189, 32125393, -451910159, -1064447283, 130656229, 5583548873 (list; graph; listen)
OFFSET

0,3

COMMENT

Row sums of the Euler related triangle A117411. Partial sums are A006495. - Paul Barry (pbarry(AT)wit.ie), Mar 16 2006

Binomial transform of [1, 0, -4, 0, 16, 0, -64, 0, 256, 0, ...] =: powers of -4 with interpolated zeros . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 02 2008]

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

G. Berzsenyi, Gaussian Fibonacci numbers, Fib. Quart., 15 (1977), 233-236.

LINKS

Index entries for Gaussian integers and primes

FORMULA

a(n)=(1/2)*((1+2I)^n+(1-2I)^n) - Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 28 2002

G.f.: (1-x)/(1-2x+5x^2); a(n)=2a(n-1)-5a(n-2); a(n)=5^(n/2)*cos(n*atan(1/3)+pi*n/4); a(n)=sum{k=0..n, sum{j=0..n-k, C(n,k-j)*C(j,n-k)}*(-4)^(n-k)}; - Paul Barry (pbarry(AT)wit.ie), Mar 16 2006

A000351(n) = a(n)^2 + A006496(n)^2. - Fabrice Baubet (intih(AT)free.fr), May 28 2007

a(n)=Sum_{k, 0<=k<=n} A124182(n,k)*(-5)^(n-k). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 01 2008]

a(n)=Sum_{k, 0<=k<=n}A098158(n,k)*(-4)^(n-k). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 14 2008]

MATHEMATICA

Table[Re[(1+2I)^n], {n, 0, 29}] - Giovanni Resta (g.resta(AT)iit.cnr.it), Mar 28 2006

PROGRAM

sage: [lucas_number2(n, 2, 5)/2 for n in xrange(0, 30)] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 08 2008

CROSSREFS

Cf. A006496.

Sequence in context: A153285 A083557 A119324 this_sequence A112286 A126261 A050097

Adjacent sequences: A006492 A006493 A006494 this_sequence A006496 A006497 A006498

KEYWORD

sign

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Signs from Christian G. Bower (bowerc(AT)usa.net), Nov 15 1998

Corrected by Giovanni Resta (g.resta(AT)iit.cnr.it), Mar 28 2006

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 17 23:40 EST 2009. Contains 171025 sequences.


AT&T Labs Research