A330739 Number of values of k, 1 <= k <= n, with A047994(k) = A047994(n), where A047994 is unitary totient function uphi(n).

1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 3, 2, 1, 1, 3, 1, 2, 3, 2, 1, 1, 1, 4, 1, 2, 1, 4, 1, 1, 1, 2, 2, 3, 1, 3, 4, 2, 1, 5, 1, 2, 1, 2, 1, 3, 1, 5, 2, 2, 1, 2, 2, 2, 3, 3, 1, 6, 1, 4, 2, 1, 3, 2, 1, 4, 1, 7, 1, 1, 1, 4, 5, 1, 2, 8, 1, 3, 1, 3, 1, 5, 1, 3, 2, 2, 1, 3, 2, 2, 4, 2, 3, 1, 1, 6, 2, 4, 1, 4, 1, 1, 7

Offset: 1

Author

Antti Karttunen, Jan 11 2020

Keywords

• nonn

Comments

Ordinal transform of A047994.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A047994.

Cf. also A081373 (ordinal transform of Euler totient function phi), A331177.

Programs

PARI

up_to = 65537;
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; };
A047994(n) = { my(f=factor(n)~); prod(i=1, #f, (f[1, i]^f[2, i])-1); };
v330739 = ordinal_transform(vector(up_to, n, A047994(n)));
A330739(n) = v330739[n];