A038237 Second line of 4-wave sequence A038197.

1, 3, 7, 26, 56, 216, 462, 1791, 3828, 14849, 31735, 123111, 263108, 1020696, 2181389, 8462447, 18085587, 70160958, 149945056, 581694636, 1243173370, 4822748423, 10306975580, 39984728949, 85453685055, 331507764639, 708484485384, 2748484256480, 5873945233705

Offset: 0

Author

Floor van Lamoen

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..700
• F. v. Lamoen, Wave sequences
• Index entries for linear recurrences with constant coefficients, signature (0,10,0,-15,0,7,0,-1).

Programs

Maple

a:= n-> (Matrix([[26, 7, 3, 1, 0, 0, -1, -1]]). Matrix(8, (i,j)-> if i=j-1 then 1 elif j=1 then [0, 10, 0, -15, 0, 7, 0, -1][i] else 0 fi)^n)[1,4]: seq (a(n), n=0..30);  # Alois P. Heinz, Jul 16 2009

Formula

G.f.: (x^5+x^4-4*x^3-3*x^2+3*x+1)/(x^8-7*x^6+15*x^4-10*x^2+1). - Alois P. Heinz, Jul 16 2009