A391066 - OEIS

A391066

a(n) is the last term of the map x -> A087207(x) starting with A019565(n) before reaching 1 or -1 if 1 is never reached.

%I #19 Dec 09 2025 22:05:01

%S 2,2,2,4,4,2,8,8,2,4,16,2,32,2,2,16,64,2,128,4,4,64,256,2,4,2,2,2,512,

%T 8,1024,32,2,2,2,2,2048

%N a(n) is the last term of the map x -> A087207(x) starting with A019565(n) before reaching 1 or -1 if 1 is never reached.

%C The position of the term in the map is given by A288569(n).

%e The table of the map is:

%e 1: 2 1

%e 2: 3 2 1

%e 3: 6 3 2 1

%e 4: 5 4 1

%e 5: 10 5 4 1

%e 6: 15 6 3 2 1

%e 7: 30 7 8 1

%e 8: 7 8 1

%e 9: 14 9 2 1

%e 10: 21 10 5 4 1

%e 11: 42 11 16 1

%e 12: 35 12 3 2 1

%e 13: 70 13 32 1

%Y Cf. A087207, A019565, A288569, A391067.

%K nonn,hard,more

%O 1,1

%A _Flávio V. Fernandes_, Nov 27 2025