A094622 Expansion of x*(11+20*x)/((1-x)*(1-10*x^2)).

0, 11, 31, 141, 341, 1441, 3441, 14441, 34441, 144441, 344441, 1444441, 3444441, 14444441, 34444441, 144444441, 344444441, 1444444441, 3444444441, 14444444441, 34444444441, 144444444441, 344444444441, 1444444444441

Offset

0,2

Comments

Previous name: Sequence whose n-th term's digits sum to 2n.

a(n) is the digit reversal of A094621(n).

Links

Table of n, a(n) for n=0..23.

Index entries for linear recurrences with constant coefficients, signature (1,10,-10).

Formula

G.f.: x*(11+20*x)/((1-x)*(1-10*x^2));

a(n) = (10^(n/2)*(31 + 13*sqrt(10) + (31 - 13*sqrt(10))*(-1)^n)/2 - 31)/9.

E.g.f.: (1/18)*exp(-sqrt(10)*x)*(31-13*sqrt(10)+(31+13*sqrt(10))*exp(2*sqrt(10)*x)-62*exp(x+sqrt(10)*x)). - Stefano Spezia, Sep 04 2019

Mathematica

LinearRecurrence[{1, 10, -10}, {0, 11, 31}, 30] (* Harvey P. Dale, May 03 2016 *)

Crossrefs

Cf. A094620, A094621.

Sequence in context: A082712 A049090 A181150 * A193645 A190781 A001604

Adjacent sequences: A094619 A094620 A094621 * A094623 A094624 A094625

Keyword

easy,nonn,base

Author

Paul Barry, May 15 2004

Status

approved