A046734 Period of A000213 mod n.

1, 1, 13, 4, 31, 13, 48, 8, 39, 31, 110, 52, 168, 48, 403, 16, 96, 39, 360, 124, 624, 110, 553, 104, 155, 168, 117, 48, 140, 403, 331, 32, 1430, 96, 1488, 156, 469, 360, 2184, 248, 560, 624, 308, 220, 1209, 553, 46, 208, 336, 155, 1248, 168, 52, 117

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..1000
• Nick Hobson, Python program for this sequence

Programs

PARI

isper(v,startAt=1)=for(k=startAt,#v-3, for(i=1,3,if(v[i]!=v[k+i],next(2)));return(k)); 0
ap(p)=my(v=vector(99),t); v[1]=v[2]=v[3]=1; for(i=4,#v,v[i]=sum(j=i-3,i-1,v[j])%p); while((t=isper(v,if(#v>99,#v/2-2,1)))==0, v=concat(v, vector(#v)); for(i=#v/2+1,#v, v[i]=sum(j=i-3,i-1,v[j])%p));t
ape(p,e)=if(p==2, return(if(e>1,p^e,1))); if(e==1, return(ap(p))); my(pe=p^e, P=ap(p)*p^(e-1), v=vector(P+3)); v[1]=v[2]=v[3]=1; for(i=4,#v,v[i]=sum(j=i-3,i-1,v[j])%pe); isper(v)
a(n)=my(f=factor(n)); lcm(vector(#f~, i, ape(f[i,1],f[i,2]))) \\ Charles R Greathouse IV, Dec 10 2015