A131081 Periodic sequence (8, 7, 4, 1, 0, 1, 4, 7).

8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8

Offset: 1

Author

Klaus Brockhaus, following a suggestion of Paul Curtz, Jun 14 2007

Keywords

• nonn
• easy
• less

Comments

Fourth column of triangular array T defined in A131074.

Links

• Index entries for linear recurrences with constant coefficients, signature (1,0,0,-1,1).

Crossrefs

Cf. A131074, A131028.

Programs

Magma

m:=105; [ [8, 7, 4, 1, 0, 1, 4, 7][(n-1) mod 8 + 1]: n in [1..m] ];

Mathematica

PadRight[{},120,{8,7,4,1,0,1,4,7}] (* Harvey P. Dale, May 20 2012 *)

PARI

{m=105; for(n=1, m, r=(n-1)%8; print1(if(r==0, 8, if(r==1||r==7, 7, if(r==2||r==6, 4, if(r==4, 0, 1)))), ","))}

Formula

a(1) = 8, a(2) = a(8) = 7, a(3) = a(7) = 4, a(4) = a(6) = 1, a(5) = 0; for n > 8, a(n) = a(n-8).

G.f.: (8-x-3*x^2-3*x^3+7*x^4)/((1-x)*(1+x^4)).