A319343 Filter sequence combining the prime signature of phi(d) from all proper divisors d of n.

1, 2, 2, 3, 2, 4, 2, 4, 5, 6, 2, 7, 2, 8, 9, 10, 2, 11, 2, 12, 13, 8, 2, 14, 15, 16, 13, 17, 2, 18, 2, 19, 13, 20, 21, 22, 2, 16, 23, 24, 2, 25, 2, 17, 26, 8, 2, 27, 28, 29, 30, 31, 2, 25, 21, 32, 23, 16, 2, 33, 2, 34, 35, 36, 37, 25, 2, 38, 13, 39, 2, 40, 2, 41, 42, 31, 43, 44, 2, 45, 46, 47, 2, 48, 49, 34, 23, 32, 2, 50, 51, 17, 52, 8, 37, 53, 2, 54, 35

Offset

1,2

Comments

Restricted growth sequence transform of A319342.

Links

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

Prog

(PARI)
up_to = 65537;
A319342(n) = { my(m=1); fordiv(n, d, if((d<n), m *= prime(A318881(d)))); (m); }; \\ Needs also code from A318881
v319343 = rgs_transform(vector(up_to, n, A319342(n)));
A319343(n) = v319343[n];

Crossrefs

Cf. A318881, A319342, A319345.

Cf. also A305983.

Sequence in context: A353565 A318835 A319353 * A300827 A144371 A323157

Adjacent sequences: A319340 A319341 A319342 * A319344 A319345 A319346

Keyword

nonn

Author

Antti Karttunen, Sep 17 2018

Status

approved