login
A038249
Third line of 4-wave sequence A038197.
0
1, 2, 9, 19, 75, 160, 622, 1329, 5157, 11021, 42756, 91376, 354484, 757588, 2938977, 6281058, 24366645, 52075371, 202020427, 431749580, 1674922950, 3579575053, 13886550633, 29677753369, 115131438424, 246054079584, 954538564968
OFFSET
0,2
FORMULA
G.f.: (-x^3-x^2+2*x+1) / (x^8-7*x^6+15*x^4-10*x^2+1). - Alois P. Heinz, Jul 16 2009
MAPLE
a:= n-> (Matrix([[ `if`(irem(n, 2)=0, 1, 2), 0, 0, 1]]). Matrix(4, (i, j)-> if i=j-1 then 1 elif j=1 then [10, -15, 7, -1][i] else 0 fi)^iquo(n, 2))[1, 1]: seq(a(n), n=0..30); # Alois P. Heinz, Jul 16 2009
CROSSREFS
Sequence in context: A274853 A264670 A026541 * A116014 A090939 A077338
KEYWORD
nonn,easy
STATUS
approved