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A193417 Numbers n such that the number of the odd divisors of phi(n) is different from the number of the odd divisors of lambda(n). 1
63, 91, 117, 126, 133, 171, 182, 189, 217, 234, 247, 252, 259, 266, 273, 275, 279, 301, 315, 333, 341, 342, 351, 364, 378, 387, 399, 403, 427, 434, 441, 451, 455, 468, 469, 481, 494, 504, 511, 513, 518, 532, 546, 549, 550, 553, 558, 559, 567, 585, 589, 602 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

n such that A193453(n) is different of A193169(n).

Numbers n such that A000265(lambda(n)) < A000265(phi(n)), where A000265(m) is the odd part (largest odd divisor) of m. - Amiram Eldar and Thomas Ordowski, Feb 04 2019

LINKS

Jinyuan Wang, Table of n, a(n) for n = 1..10000

EXAMPLE

63 is in the sequence because phi(63) = 36 with 3 odd divisors {1, 3, 9} and lambda(63) = 6 with only 2 odd divisors {1, 3}.

MATHEMATICA

f[n_] := Block[{d = Divisors[EulerPhi[n]]}, Count[OddQ[d], True]]; Table[f[n], {n, 500}]; g[n_] := Block[{e = Divisors[CarmichaelLambda[n]]}, Count[OddQ[e], True]]; Table[g[n], {n, 500}]; a={}; Do[If[ f[n] != g[n], AppendTo[a, n]], {n, 500}]; a

PROG

(PARI) is(n) = my(cp = eulerphi(n), cn=cp>>valuation(cp, 2), cl=lcm(znstar(n)[2])); cl = cl >> valuation(cl, 2); numdiv(cl) != numdiv(cn) \\ David A. Corneth, Feb 18 2019

CROSSREFS

Cf. A000010, A000265, A002322, A053575.

Sequence in context: A043186 A039363 A043966 * A062375 A253021 A039480

Adjacent sequences:  A193414 A193415 A193416 * A193418 A193419 A193420

KEYWORD

nonn

AUTHOR

Michel Lagneau, Jul 26 2011

STATUS

approved

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Last modified October 16 05:54 EDT 2019. Contains 328045 sequences. (Running on oeis4.)