0,7

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

a(n) =A090622(n, 4) =[A011371(n)/2] =[([n/2]+[n/4]+[n/8]+[n/16]+...)/2].

a(6)=2 since 6!=720 =4^2*45.

IntegerExponent[Range[0, 100]!, 4] (* Vincenzo Librandi, Mar 10 2013 *)

(PARI) a(n) = valuation( n!, 4 ); /* Joerg Arndt, Mar 10 2013 */

Cf. A011371, A054861, A027868, A054896.

Sequence in context: A069924 A225559 A082479 * A186704 A067434 A336348

Adjacent sequences: A090613 A090614 A090615 * A090617 A090618 A090619

nonn

Henry Bottomley, Dec 06 2003

approved