OFFSET
1,6
COMMENTS
Ordinal transform of A309639.
For all n, a(A000961(n)) = 1, but the sequence obtains value 1 also on other n that are not prime powers. In range 1..65537 these extra 1's occur at n = 69, 201, 407, 505, 576, 869, 1791, 5157, 9383, 9691, 10219, 10571, 10991, 12575, 12731, 13343, 13739, 14179, 14483, 14693, 16173, 16723, 23347, 24209, 26233, 26377, 37393, 44407, 46089, 53707, 62063.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
PROG
(PARI)
ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om, invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om, invec[i], (1+pt))); outvec; };
v330753 = ordinal_transform(vector(up_to, n, A309639(n)));
A330753(n) = v330753[n];
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Dec 30 2019
STATUS
approved