A079700 a(n) is the 2-adic valuation of the n-th even nontotient.

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

Offset

1,7

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Maxim Rytin, Finding the Inverse of Euler Totient Function (1999).

Formula

a(n) = A007814(A005277(n)). - Michel Marcus, Jul 01 2017

Example

A005277(10)=86, therefore a(10)=1.

Mathematica

IntegerExponent[Select[Range[2, 500, 2], invphi[#] == {}&], 2] (* Jean-François Alcover, Jul 01 2017, using Maxim Rytin's invphi function *)

Prog

(PARI) lista(nn)=forstep(n=2, nn, 2, if (!istotient(n), print1(valuation(n, 2), ", ")); ); \\ Michel Marcus, Jul 01 2017

Crossrefs

Cf. A005277, A007814.

Sequence in context: A077619 A376141 A030600 * A357722 A374540 A135362

Adjacent sequences: A079697 A079698 A079699 * A079701 A079702 A079703

Keyword

nonn

Author

Jon Perry, Jan 31 2003

Extensions

More terms from Jean-François Alcover, Jul 01 2017

Offset corrected by Charles R Greathouse IV, Jul 02 2017

Status

approved