login
A155196
a(n)=7*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=6, a(2)=42 .
1
1, 6, 42, 300, 2142, 15294, 109200, 779694, 5567058, 39749100, 283810758, 2026424406, 14468781600, 103307895606, 737624050842, 5266676251500, 37604357811342, 268497180930894, 1917084624327600, 13688089551224094
OFFSET
0,2
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
MATHEMATICA
Join[{1}, LinearRecurrence[{7, 1}, {6, 42}, 20]] (* Harvey P. Dale, Sep 04 2014 *)
CROSSREFS
Sequence in context: A156361 A216517 A055272 * A147838 A127628 A111602
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Jan 21 2009
STATUS
approved