OFFSET
0,3
COMMENTS
LINKS
Index entries for linear recurrences with constant coefficients, signature (10,-37,60,-36).
FORMULA
E.g.f.: x*(exp(3*x) - exp(2*x)).
G.f.: x^2*(2 - 5*x)/(1 - 5*x + 6*x^2)^2. - Stefano Spezia, May 12 2021
EXAMPLE
a(3)=15 since the strings are the 3 permutations of 011, the 6 permutations of 012 and the 6 permutations of 013.
MATHEMATICA
LinearRecurrence[{10, -37, 60, -36}, {0, 0, 2, 15}, 29] (* Amiram Eldar, May 11 2021 *)
Table[n(3^(n-1)-2^(n-1)), {n, 0, 30}] (* Harvey P. Dale, Mar 13 2022 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Enrique Navarrete, May 11 2021
STATUS
approved