A202206 a(n) = 3*a(n-1)+3*a(n-2) with a(0)=1 and a(1)=2.
1, 2, 9, 33, 126, 477, 1809, 6858, 26001, 98577, 373734, 1416933, 5372001, 20366802, 77216409, 292749633, 1109898126, 4207943277, 15953524209, 60484402458, 229313780001, 869394547377, 3296124982134
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (3,3).
Programs
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Mathematica
LinearRecurrence[{3,3},{1,2},30] (* Harvey P. Dale, Aug 03 2020 *) -
PARI
Vec((1-x)/(1-3*x-3*x^2)+O(x^99)) \\ Charles R Greathouse IV, Jan 31 2012
Formula
G.f.: (1-x)/(1-3*x-3*x^2).