Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

1,4

a(n) = A001222(A003586(n));

a(n) = A022328(n) + A022329(n);

A086414(n) <= A086415(n) <= a(n).

Zak Seidov, Table of n, a(n) for n = 1..10000

a(n) = i+j for 3-smooth numbers n = 2^i*3^j (A003586).

a(n) = A001222(A033845(n))-2. - Enrique PĂ©rez Herrero, Jan 04 2012

Sequence in context: A115727 A115726 A086413 * A073453 A123229 A127095

Adjacent sequences: A069349 A069350 A069351 * A069353 A069354 A069355

nonn

Reinhard Zumkeller, Mar 18 2002

Edited by N. J. A. Sloane, Oct 27 2008 at the suggestion of R. J. Mathar.

approved