Search: id:A102423 Results 1-1 of 1 results found. %I A102423 %S A102423 1,1,1,1,1,1,1,17,17,17,1,1,1,17,1,1,1,1,1,1,1,17,1,1,1,1,1,1,1,1,17,1, %T A102423 1,1,17,1,1,17,17,1,1,1,1,1,1,1,1,17,17,1,1,1,1,17,17,1,1,1,1,1,17,17, 1, %U A102423 1,1,1,1,17,17,1,1,1,1,1,1,1,17,1,1,1,1,1,1,1,17,17,17,1,1,1,1,1,1,1,1 %N A102423 Start at 2n+1, iterate the map x -> A102421(x); sequence gives smallest number in resulting cycle, or -1 if the trajectory never cycles. %C A102423 See A102421 for further comments. %t A102423 nextx[x_Integer] := Block[{a = x}, a = 3a + 1; While[EvenQ@a, a /= 2]; a = 3a - 1; While[EvenQ@a, a /= 2]; a]; f[n_] := NestWhile[nextx, n, MemberQ[{1, 17, 19, 43, 97, 109}, # ] &]; Table[ If[ f[2n + 1] == 1, 1, 17], {n, 0, 94}] (* Robert G. Wilson v Sep 20 2006 *) %Y A102423 Sequence in context: A004458 A082123 A050256 this_sequence A010856 A060360 A081702 %Y A102423 Adjacent sequences: A102420 A102421 A102422 this_sequence A102424 A102425 A102426 %K A102423 nonn %O A102423 0,8 %A A102423 N. J. A. Sloane (njas(AT)research.att.com), based on email from Dan Asimov (dasimov(AT)earthlink.net), Sep 15 2006 %E A102423 More terms from Robert G. Wilson v Sep 20 2006 Search completed in 0.001 seconds