A155196 a(n)=7*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=6, a(2)=42 .
1, 6, 42, 300, 2142, 15294, 109200, 779694, 5567058, 39749100, 283810758, 2026424406, 14468781600, 103307895606, 737624050842, 5266676251500, 37604357811342, 268497180930894, 1917084624327600, 13688089551224094
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (7, 1).
Programs
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Mathematica
Join[{1},LinearRecurrence[{7,1},{6,42},20]] (* Harvey P. Dale, Sep 04 2014 *)
Formula
G.f.: (1-x-x^2)/(1-7*x-x^2).
a(n) = Sum_{k, 0<=k<=n} A155161(n,k)*6^k. - Philippe Deléham, Feb 08 2012