A096866 Function A062402(x) = sigma(phi(x)) is iterated. Starting with n, a(n) is the smallest term arising in trajectory, either in transient or in terminal cycle.

1, 1, 3, 3, 5, 3, 7, 7, 7, 7, 7, 7, 13, 7, 15, 15, 17, 7, 19, 15, 21, 7, 23, 15, 25, 26, 27, 28, 29, 15, 31, 31, 28, 31, 31, 28, 37, 31, 31, 31, 31, 28, 43, 28, 31, 28, 31, 31, 49, 28, 51, 31, 53, 31, 31, 31, 57, 31, 31, 31, 61, 31, 63, 63, 65, 28, 67, 63, 31, 31, 71, 31, 73, 74

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..16384

Example

n=240: list={240,127,312,[252,195],252,...}, a(240)=127, a transient;
n=254: list={254,312,[252,195],252,...}, a(254)=195, a recurrent term.

Mathematica

gf[x_] :=DivisorSigma[1, EulerPhi[x]] gite[x_, hos_] :=NestList[gf, x, hos] Table[Min[gite[w, 20]], {w, 1, 256}]

Prog

(Scheme) (define (A096866 n) (let loop ((visited (list n)) (m n)) (let ((next (A062402 (car visited)))) (cond ((member next visited) m) (else (loop (cons next visited) (min m next))))))) ;; Antti Karttunen, Nov 18 2017

Crossrefs

Cf. A062401, A062402, A096862, A096863, A096864 (largest term), A096993.

Cf. also A096865.

Sequence in context: A215495 A335115 A299149 * A348158 A360469 A320045

Adjacent sequences: A096863 A096864 A096865 * A096867 A096868 A096869

Keyword

nonn

Author

Labos Elemer, Jul 21 2004

Status

approved