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A158561 a(n)=((2^n)*((2^n)+1) - (2^(n-1))*((2^(n-1))+1))/2, a(1)=3. 1
3, 7, 26, 100, 392, 1552, 6176, 24640, 98432, 393472, 1573376, 6292480, 25167872, 100667392, 402661376, 1610629120, 6442483712, 25769869312, 103079346176, 412317122560, 1649267965952, 6597070815232, 26388281163776, 105553120460800, 422212473454592 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) gives the number of elements with the length of n-digits, base B, in the addition matrix <0;B^n -1> x <0;B^n -1>. a(1)=B*(B+1)/2. a(n)=((B^n)*((B^n)+1) - (B^(n-1))*((B^(n-1))+1))/2.

Essentially the same as A049775. [From R. J. Mathar, Mar 26 2009]

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (6,-8)

FORMULA

x*(1-x)*(3-8*x)/((1-2*x)*(1-4*x)) [From Jaume Oliver Lafont, Mar 27 2009]

G.f.: (3-11*x+8*x^2)/(1-6*x+8*x^2). - Harvey P. Dale, Feb 25 2017

MATHEMATICA

LinearRecurrence[{6, -8}, {3, 7, 26}, 30] (* Harvey P. Dale, Feb 25 2017 *)

CROSSREFS

Cf. A000217

Cf. A006516. [From Jaume Oliver Lafont, Mar 27 2009]

Sequence in context: A215018 A069738 A057005 * A252786 A108217 A120120

Adjacent sequences:  A158558 A158559 A158560 * A158562 A158563 A158564

KEYWORD

easy,nonn

AUTHOR

Ctibor O. Zizka, Mar 21 2009

EXTENSIONS

More terms from Harvey P. Dale, Feb 25 2017

STATUS

approved

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Last modified April 17 16:12 EDT 2021. Contains 343063 sequences. (Running on oeis4.)