OFFSET
1,1
LINKS
Colin Barker, Table of n, a(n) for n = 1..950
Math.Stackexchange.Com, Marko Riedel et al., Decreasing sequence numbers
Index entries for linear recurrences with constant coefficients, signature (24,-165,242).
FORMULA
a(n) = (10/9) * n * 11^n - (11/81) * (11^n-2^n).
G.f.: 11 * z * (1-z) / ((1-11z)^2 * (1-2z)).
a(n) = 24*a(n-1)-165*a(n-2)+242*a(n-3) for n>3. - Colin Barker, Jul 20 2016
EXAMPLE
a(2) = 253 because 210+21+20+2 = 253.
MAPLE
A274129 := n -> 10/9*n*11^n - 11/81*(11^n-2^n);
MATHEMATICA
CoefficientList[Series[11*x*(1 - x)/((1 - 11*x)^2*(1 - 2*x)), {x, 0, 100} ], x] (* G. C. Greubel, Jul 07 2016 *)
PROG
(PARI) Vec(11*x*(1-x)/((1-11*x)^2*(1-2*x)) + O(x^20)) \\ Colin Barker, Jul 20 2016
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Marko Riedel, Jul 07 2016
STATUS
approved