This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A214635 #18 Oct 18 2014 09:11:47
%S A214635 1,1,1,1,3,1,1,1,3,3,1,1,4,1,3,1,6,3,1,3,1,1,1,1,3,4,3,1,1,3,1,1,1,6,
%T A214635 3,3,1,1,4,3,7,1,1,1,3,1,4,1,6,3,6,4,1,3,3,1,1,1,3,3,10,1,3,1,12,1,1,
%U A214635 6,1,3,11,3,6,1,3,1,1,4,4,3,9,7,5,1,6,1,1,1,14,3,4,1,1,4,3,1,3,6,3
%N A214635 Period of A213437 mod n.
%F A214635 Empirically:
%F A214635 A214635(2^n) = 1, A214635(5^n) = A214635(10^n) = 3, for all n>0.
%F A214635 A214635(3^n) = A214635(6^n) = (1, 3, 3, 9, 27, 81, ...) = 3^(n-2) for n>2.
%F A214635 A214635(15^n) = (3,3,3,9,27,81,...) = A214635(3^n) for n>1.
%F A214635 A214635(7^n) = (1,6,42,294,...) = 6*7^(n-2) for n>1.
%F A214635 A214635(11^n) = (1,20,220,2420,...) = 20*11^(n-2) for n>1. - _M. F. Hasler_, Jul 24 2012
%o A214635 (PARI) A214635(n,N=99)={my(a=[Mod(1,n)]); for(n=1,N-1,a=concat(a,a[n]+(a[n]+1)*prod(k=1,n-1,a[k])));for(p=1,N\3,forstep(m=N,p+1,-1,a[m]==a[m-p]&next;3*m>N&next(2);return(p));return(p))} /* the 2nd optional parameter must be taken large enough, at least 3 times the period length and starting position. The script returns zero if the period is not found (probably due to these constraints). */
%Y A214635 Cf. A213437, A214636.
%K A214635 nonn
%O A214635 1,5
%A A214635 _David Applegate_, _M. F. Hasler_ and _N. J. A. Sloane_, Jul 23 2012