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
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
KEYWORD
easy,nonn,base
AUTHOR
Paul Barry, May 15 2004
STATUS
approved