Generalized Fibonacci sequence to higher order

 

Tribonacci sequence(order 3)

 

f(0)=0

f(1)=0

f(2)=1

f(i)= f(i-3)+f(i-2)+f(i-1)    for i=3,4,5, . . .

 

Tetranacci sequence(order 4)

 

f(0)=0

f(1)=0

f(2)=0

f(3)=1

f(i)= f(i-4)+f(i-3)+f(i-2)+f(i-1)    for i=4,5,6, . . .

 

n-nacci sequence(order n)

 

f(0)=0

f(1)=0

f(2)=0

.

.

.

f(n-2)=0

f(n-1)=1

f(i)= f(i-n)+f(i-(n-1))+. . . +f(i-3)+f(i-2)+f(i-1)    for i=n,n+1,n+2, . . .

 

In general, generalize n-nacci sequence

 

f(0)=x[0]

f(1)=x[1]

f(2)=x[2]

.

.

.

f(n-2)=x[n-2]

f(n-1)=x[n-1]

f(i)= c[n]*f(i-n)+c[n-1]*f(i-(n-1))+. . . +c[3]*f(i-3)+c[2]*f(i-2)+c[1]*f(i-1)    for i=n,n+1,n+2, . . .

 

examples:

Padovan sequence   x={1,1,1} and c={0,1,1}

n-nacci sequence     x={0,0, . . . ,0,1} and c={1,1, . . . ,1,1}

 

An application: multiple recursive generator

 

x[i]=(a1*x[i-1]+a2*x[i-2]+a3*x[i-3]+a4*x[i-4]+a5*x[i-5]) mod m.

 

for a1=107374182, a2=0, a3=0, a4=0, a5=104480, and m=2^31-1.

where initial ate set by a certain rule or at random.