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. [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
G.f.: x*(1-x)*(3-8*x)/((1-2*x)*(1-4*x)). [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
KEYWORD
easy,nonn
AUTHOR
Ctibor O. Zizka, Mar 21 2009
EXTENSIONS
More terms from Harvey P. Dale, Feb 25 2017
STATUS
approved