OFFSET
0,1
FORMULA
1->{2}, 2->{3, 4}, 3->{2, 4}, 4->{2, 5, 6}, 5->{3, 6}, 6->{1, 4, 5}
EXAMPLE
[1] -> [2] -> [3,4] -> [2,4,2,5,6] -> [3,4,2,5,6,3,4,3,6,1,4,5] -> ... Lengths of iterates is 1,1,2,5,12,28,... = A034943. - Michael Somos
MATHEMATICA
s[1] = {2}; s[2] = {3, 4}; s[3] = {2, 4}; s[4] = {2, 5, 6}; s[5] = {3, 6}; s[6] = {1, 4, 5}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] aa = p[7]
PROG
(PARI) {a(n)=my(A); if(n<1, 0, A=[2]; while(length(A)<n||A[1]!=2, A=concat(vector(length(A), k, [[2], [3, 4], [2, 4], [2, 5, 6], [3, 6], [1, 4, 5]][A[k]]))); A[n])} /* Michael Somos, May 16 2005 */
CROSSREFS
KEYWORD
nonn,uned
AUTHOR
Roger L. Bagula, May 13 2005
STATUS
approved