A193169 Number of odd divisors of lambda(n).

1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 2, 1, 1, 1, 2, 3, 1, 2, 2, 2, 1, 2, 2, 3, 2, 2, 1, 4, 1, 2, 1, 2, 2, 3, 3, 2, 1, 2, 2, 4, 2, 2, 2, 2, 1, 4, 2, 1, 2, 2, 3, 2, 2, 3, 2, 2, 1, 4, 4, 2, 1, 2, 2, 4, 1, 2, 2, 4, 2, 3, 3, 2, 3, 4, 2, 4, 1

Offset: 1

Author

Michel Lagneau, Jul 22 2011

Keywords

• nonn

Comments

Lambda is the function in A002322.

Examples

			a(19) = 3 because lambda(19) = 18 and the 3 odd divisors are {1, 3, 9}.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002322.

Cf. A027750, A001227.

Programs

Haskell

a193169 = length . filter odd . a027750_row . a002322
-- Reinhard Zumkeller, Sep 02 2014

Mathematica

f[n_] := Block[{d = Divisors[CarmichaelLambda[n]]}, Count[OddQ[d], True]]; Table[f[n], {n, 80}]

PARI

a(n) = sumdiv(lcm(znstar(n)[2]), d, (d%2)); \\ Michel Marcus, Mar 18 2016

Formula

a(n) = A001227(A002322(n)). - Michel Marcus, Mar 18 2016